Points of the compass
The points of the compass, specifically on the compass rose, mark divisions of a compass, such divisions may be referred to as winds or directions. A compass point allows reference to a heading in a general or colloquial fashion. A compass is primarily divided into the four cardinal points—north, south and these are often further subdivided by the addition of the four intercardinal directions—northeast between north and east, southeast and northwest —to indicate the eight principal winds. In meteorological usage, further intermediate points between cardinal and ordinal points, such as north-northeast between north and northeast, are added to give the sixteen points of a wind compass, for most applications, the fractional points have been superseded by degrees measured clockwise from North. In ancient China 24 points of the compass were used, measuring fifteen degrees between points. The names of the compass directions follow the 32-point wind compass rose follow these rules, The cardinal directions are north, south, the ordinal directions are northeast, southeast and northwest, formed by bisecting the angle of the cardinal winds.
The name is merely a combination of the cardinals it bisects, the eight principal winds are the cardinals and ordinals considered together, that is N, NE, E, SE, S, SW, W, NW. Each principal wind is 45° from its neighbour, the principal winds form the basic eight-wind compass rose. The eight half-winds are the points obtained by bisecting the angles between the principal winds, the half-winds are north-northeast, east-northeast, east-southeast, south-southeast, south-southwest, west-southwest, west-northwest and north-northwest. Notice that the name is constructed simply by combining the names of the winds to either side, with the cardinal wind coming first. The eight principal winds and the eight half-winds together yield a 16-wind compass rose, all of the above named points plus the sixteen quarter winds listed in the next paragraph define the 32 points of the wind compass rose. The sixteen quarter winds are the points obtained by bisecting the angles between the points on a 16-wind compass rose.
The name of a quarter-wind is X by Y, where X is a principal wind, so northeast by east means one quarter from NE towards E, southwest by south means one quarter from SW towards S. The eight principal winds, eight half-winds and sixteen quarter winds together yield a 32-wind compass rose, in the mariners exercise of boxing the compass, all thirty-two points of the compass are named in clockwise order. The title of the Alfred Hitchcock 1959 movie, North by Northwest, is not a direction point on the 32-wind compass. The traditional compass rose of eight winds was invented by seafarers in the Mediterranean Sea during the Middle Ages. This Italianate patois was used to designate the names of the winds on the compass rose found in mariner compasses. Tramutana, Grecho, Xaloc, Libezo, Mezzodi, Magistro, etc
Postcodes in the United Kingdom
Postal codes used in the United Kingdom are known as postcodes. They are alphanumeric and were adopted nationally between 11 October 1959 and 1974, having been devised by the GPO, a full postcode is known as a postcode unit and designates an area with a number of addresses or a single major delivery point. For example, the postcode of the University of Roehampton in London is SW15 5PU, the postcode of GCHQ is GL51 0EX, where GL signifies the postal town of Gloucester. The postal town refers to an area and does not relate to a specific town. GL51 is one of the postcodes for the town of Cheltenham which is where GCHQ is located, the London post town covers 40% of Greater London. On inception it was divided into ten districts, EC, WC, N, NE, E, SE, S, SW, W. The S and NE sectors were abolished and these divisions changed little, usually only changed for operational efficiency. Some older road signs in Hackney still indicate the North East sector/district, following the successful introduction of postal districts in London, the system was extended to other large towns and cities.
Liverpool was divided into Eastern, Northern and Western districts in 1864/65, in 1917 Dublin – still part of the United Kingdom – was divided into numbered postal districts. These continue in use in a form by An Post. In 1923 Glasgow was divided in a way to London. In January 1932 the Postmaster General approved the designation of some urban areas into numbered districts. In November 1934 the Post Office announced the introduction of numbered districts in every town in the United Kingdom large enough to justify it. Pamphlets were issued to each householder and business in ten areas notifying them of the number of the district in which their premises lay, the pamphlets included a map of the districts, and copies were made available at local head post offices. The public were invited to include the district number in the address at the head of letters. A publicity campaign in the following year encouraged the use of the district numbers, the slogan for the campaign was For speed and certainty always use a postal district number on your letters and notepaper. A poster was fixed to every box in the affected areas bearing the number of the district.
Every post office in the district was to display this information
London Ambulance Service
It is one of the busiest ambulance services in the world, and the busiest in the United Kingdom, providing care to more than 8.6 million people, who live and work in London. The service is currently under the leadership of chief executive Dr Fionna Moore MBE, the service employ around 4,500 staff. In exceptional cases, or where the service deems in necessary, specialist teams can be deployed from within the service, such as the Hazardous Area Response Team and these teams are specially trained and equipped to deal with incidents such as working at height or in confined spaces. It is one of 10 ambulance trusts in England providing emergency medical services, there is no charge to patients for use of the service, as every person in England has the right to the attendance of an ambulance in an emergency. The LAS responded to over 1.8 million calls for assistance, incidents rose by 20,000 in 2015/16, putting more pressure on the service. All 999 calls from the public are answered at the Emergency Operations Centre in Waterloo, to assist, the services command and control system is linked electronically with the equivalent system for Londons Metropolitan Police.
This means that police updates regarding specific jobs will be updated directly on the computer-aided dispatch log, to be viewed by the EOC, the first became operational at The South Eastern Fever Hospital, Deptford, in October 1883. In all, six hospitals operated horse-drawn land ambulances, putting almost the whole of London within three miles of one of them, each ambulance station included accommodation for a married superintendent and around 20 drivers, horse keepers and attendants, laundry staff and domestic cleaners. At Deptford, in order to transfer patients between the hospitals at Joyce Green and Long Reach near Gravesend, a horse-drawn ambulance tramway was constructed in 1897, in 1902, the MAB introduced a steam driven ambulance and in 1904, their first motor ambulance. The last horse-drawn ambulances were used on 14 September 1912, although the MAB was legally supposed to be transporting only infectious patients, it increasingly carried accident victims and emergency medical cases.
Also in 1915, the MAB Ambulance Section were the first public body to women drivers. By July 1916 the London County Council Ambulance Corps was staffed entirely by women, the LCC took control of the River Ambulance Service, but it was disbanded in 1932. During World War II, the London Auxiliary Ambulance Service was operated by over 10,000 auxiliaries, mainly women and they ran services from 139 Auxiliary Stations across London. A plaque at one of the last to close, Station 39 in Weymouth Mews, near Portland Place, in 1948 the National Health Service Act made it a requirement for ambulances to be available for anyone who needed them. On 1 April 1996, the LAS left the control of the South West Thames Regional Health Authority, as an NHS Trust, the LAS has a Trust Board consisting of 12 members. The board includes, a chairman, five of the Service’s executive directors. Special events in London are co-ordinated from the Services event control room, located in east London, during mass casualty incidents, the command structure works on three levels, gold and bronze.
Silver control, tactical command, from a point in the vicinity of the incident, Bronze control
Bishopshalt School is a secondary school and sixth form with academy status based in the London Borough of Hillingdon. It has specializations in music and the performing arts, between 2013 and 2014, the school was used for scenes in the BBC sitcom Big School. The current building within which the school is housed was built in 1858, the school dates back to 1907 when it was first established as Uxbridge County School in the Greenway. It was designed by the architect H. G. Crothall for the Middlesex Education Committee, the Middlesex Education Committee purchased the present site for £6900 in 1925 and in 1928 the school moved there. The original buildings in the Greenway became part of Uxbridge High School, on 6 October the school was officially opened by Sir John Reith, the Director-General of the BBC. Walter Wilks Sawtell was headmaster of the school from its founding in 1907 until 1929 and he remained in the position to oversee the move of the school, before resigning to become rector of Madehurst in Sussex.
The school name was changed to Bishophalt School in 1930 to acknowledge it was no longer in Uxbridge and it is derived from the history of the site as for 500 years, the Bishops of Worcester rested at the grounds of the school on their journeys to and from London. A Cierva C.19 Mk.3 Autogiro landed on the field in July 1931, piloted by the Cierva Autogiro Companys Flying Manager Reginald A. C. Brie. During the Second World War, the school was used for rallies, randalls of Uxbridge, a local family-owned department store, donated three oak chairs to the school in October 1949. In 1969, the air raid shelters were removed and replaced by a car park. The shelters had been built in 1939 but remained because of the threat of the Cold War, the London Borough of Hillingdon held council meetings in the school hall while the Civic Centre in Uxbridge was under construction. In 1977 the school changed from a school to a comprehensive. An episode of Jeeves and Wooster starring Hugh Laurie and Stephen Fry was filmed in the school grounds.
The school has used as a filming location, for the film adaptation of Angus and Perfect Snogging, directed by Gurinder Chadha. The current Headmaster is Mr Kimberly Rowe, who started in September 2011, prior Headteachers are, Mr David Bocock, Mr Vincent Hodkinson, Dr Leslie Bather. Bishopshalt School specialises in music and the performing arts and it has its own large playing fields and an ornamental garden specifically for the 6th form students. Bishopshalt has six houses, five named after bishops that rested at the old mansion, on their first day out from London, cranmer, De Salis, Manor and Worcester are the houses. The school motto is Fidelis, meaning Faithful, Bishopshalt School runs a dramatic society named Bishopshalt Operatic and Dramatic Society, known as BODS
In England, a civil parish is a territorial designation which is the lowest tier of local government below districts and counties, or their combined form, the unitary authority. It is a parish, in contrast to an ecclesiastical parish. A civil parish can range in size from a town with a population of around 80,000 to a single village with fewer than a hundred inhabitants. In a limited number of cases a parish might include a city where city status has been granted by the Monarch. Reflecting this diverse nature, a parish may be known as a town, village. Approximately 35% of the English population live in a civil parish, as of 31 December 2015 there were 10,449 parishes in England. On 1 April 2014, Queens Park became the first civil parish in Greater London, before 2008 their creation was not permitted within a London borough. The division of land into ancient parishes was linked to the system, parishes. The manor was the unit of local administration and justice in the early rural economy. Later the church replaced the court as the rural administrative centre.
After the dissolution of the monasteries, the power to levy a rate to fund relief of the poor was conferred on the authorities by the Act for the Relief of the Poor 1601. Both before and after this optional social change, local charities are well-documented, the parish authorities were known as vestries and consisted of all the ratepayers of the parish. As the number of ratepayers of some parishes grew, it increasingly difficult to convene meetings as an open vestry. In some, mostly built up, areas the select vestry took over responsibility from the body of ratepayers. This innovation improved efficiency, but allowed governance by a self-perpetuating elite, by the 18th century, religious membership was becoming more fractured in some places, due for instance to the progress of Methodism. The legitimacy of the parish came into question and the perceived inefficiency. Sanitary districts covered England in 1875 and Ireland three years later, the replacement boards were each entitled to levy their own rate in the parish.
The church rate ceased to be levied in many parishes and became voluntary from 1868, the ancient parishes diverged into two distinct systems of parishes during the 19th century
Hillingdon London Borough Council
Hillingdon London Borough Council is the local authority for the London Borough of Hillingdon in Greater London, England. It is a London borough council, one of 32 in the United Kingdom capital of London, Hillingdon is divided into 22 wards, electing a total of 65 councillors. There have previously been a number of authorities responsible for the Hilligdon area. The current local authority was first elected in 1964, a year before coming into its powers. Hillingdon replaced Uxbridge Borough Council and Harlington Urban District Council, Ruislip-Northwood Urban District Council and Yiewsley and it was envisaged through the London Government Act 1963 that Hillingdon as a London local authority would share power with the Greater London Council. As an outer London borough council it has been an education authority since 1965 and this arrangement lasted until 1986 when Hillingdon London Borough Council gained responsibility for some services that had been provided by the Greater London Council, such as waste disposal.
The council has alternated between Conservative, Labour Party and no overall control since it was first elected in 1964
He had previously been an MP for the Henley constituency from 2001 to 2008 and was Mayor of London from 2008 to 2016. Johnson was formerly a historian and journalist. A member of the Conservative Party, Johnson identifies as a conservative and has been associated with both economically and socially liberal policies. Born in New York City to wealthy upper-middle class English parents, Johnson was educated at the European School of Brussels, Ashdown House School and he studied Classics at Balliol College, where he was elected president of the Oxford Union in 1986. He was assistant editor from 1994 to 1999 before taking the editorship of The Spectator from 1999 to 2005, joining the Conservatives, he was elected MP for Henley in 2001, and under Michael Howard and David Cameron he was in the Shadow Cabinet. Mostly adhering to the Conservatives party line, he adopted a more socially liberal stance on issues like LGBT rights in parliamentary votes. Making regular television appearances, writing books, and remaining active in journalism, selected as Conservative candidate for the London mayoral election of 2008, Johnson defeated Labour incumbent Ken Livingstone and resigned his seat in parliament.
In 2012, he was re-elected mayor, again defeating Livingstone, in 2015 he was elected MP for Uxbridge and South Ruislip, stepping down as mayor the following year. In 2016, Johnson became a prominent figure in the successful Vote Leave campaign to withdraw the United Kingdom from the European Union, Johnson is a controversial figure in British politics and journalism. Supporters have praised him as an entertaining and popular figure with appeal beyond traditional Conservative voters, conversely, he has been criticised by figures on both the left and right, accused of elitism and laziness, and using racist language. Johnson is the subject of biographies and a number of fictionalised portrayals. Johnson was born on 19 June 1964 at a hospital on the Upper East Side of Manhattan in New York City and his birth was registered with both the US authorities and the citys British Consulate and he was granted both American and British citizenship. His father, Stanley Johnson, was studying economics at Columbia University.
Stanleys paternal grandfather was Circassian–Turkish journalist Ali Kemal, while his other ancestry is English and French, Stanley had married Johnsons mother, Charlotte Johnson Wahl, in 1963, before they moved to the United States, she was an artist from a family of liberal intellectuals. She was the granddaughter of Americans Elias Avery Lowe, a palaeographer of Russian Jewish descent, and Helen Tracy Lowe-Porter, in reference to his varied ancestry, Johnson has described himself as a one-man melting pot – with a combination of Muslims and Christians as great-grandparents. Johnson was given his name of Boris after a Russian émigré the couple had once met in Mexico. Johnsons parents were living in an apartment opposite the Chelsea Hotel, although they soon embarked on a tour of Canada. In September 1964, they returned to Britain, enabling Charlotte to study for a degree at the University of Oxford and she lived with her son in Summertown and gave birth to a daughter, Rachel, in 1965
London Borough of Hillingdon
The London Borough of Hillingdon is the westernmost borough in Greater London, England which had a population of 273,936 according to the 2011 Census. It was formed from the districts of Hayes and Harlington, Ruislip-Northwood, today, Hillingdon is home to Heathrow Airport and Brunel University, and is the second largest of the 32 London boroughs by area. Hillingdon Council governs the borough, with its headquarters in the Civic Centre in Uxbridge, for administrative purposes, the borough is split into North and South Hillingdon. The councils involved were unable to decide upon a name, with Keith Joseph suggesting Uxbridge in October 1963. The coat of arms for the London Borough of Hillingdon was granted on 22 March 1965, between 1973 and 1978, the boroughs civic centre was built in Uxbridge. The borough has been twinned with the French town of Mantes-la-Jolie, the twinning programme was reviewed in 2011 and it was suggested that the link with Schleswig be ended owing to a lack of contact between the towns.
In December 2011, the borough decided instead to end the link with a second German town, citing administrative problems. Population grew from 2001–2011 by 11. 5% -4. 4% above the England and Wales mean of 7. 1% - as part of the fastest population-growth area, by comparison Merton and Bromley had growth of 4. 5% and Tower Hamlets had growth of 26. 4%. Households increased from 2001–2011 by 3. 3%, and the number of people per household was 2.7. The borough is governed by a council, known interchangeably by the full name. It is split into wards represented by 65 Conservative and Labour councillors, a cabinet and leader are elected annually. The present leader of the council is Cllr, ray Puddifoot MBE of the Conservative Party. Elections for councillors are held four years. A Mayor is chosen yearly by councillors, the role is largely ceremonial, the present mayor is Councillor George Cooper, who was elected in May 2015. In the London assembly elections and Hillingdon Borough form a constituency with one member as there are eleven London-wide members.
At the same election in 2012 Conservative mayoral candidate Boris Johnson won the largest share of Hillingdons votes in becoming elected Mayor of London for a second term. The British Governments UK Visas and Immigration has two immigration removal centres, Colnbrook Immigration Removal Centre and Harmondsworth Immigration Removal Centre in Harmondsworth. The borough includes RAF Northolt and the sites of RAF Eastcote, RAF South Ruislip, RAF West Drayton, RAF Ruislip 4MU, RAF West Ruislip
Conservative Party (UK)
The Conservative Party, officially the Conservative and Unionist Party, is a political party in the United Kingdom. It is currently the party, having won a majority of seats in the House of Commons at the 2015 general election. The partys leader, Theresa May, is serving as Prime Minister. It is the largest party in government with 8,702 councillors. The Conservative Party is one of the two major political parties in the United Kingdom, the other being its modern rival. The Conservative Partys platform involves support for market capitalism, free enterprise, fiscal conservatism, a strong national defence, deregulation. In the 1920s, the Liberal vote greatly diminished and the Labour Party became the Conservatives main rivals, Conservative Prime Ministers led governments for 57 years of the twentieth century, including Winston Churchill and Margaret Thatcher. Thatchers tenure led to wide-ranging economic liberalisation, the Conservative Partys domination of British politics throughout the twentieth century has led to them being referred to as one of the most successful political parties in the Western world.
The Conservatives are the joint-second largest British party in the European Parliament, with twenty MEPs, the party is a member of the Alliance of Conservatives and Reformists in Europe Europarty and the International Democrat Union. The party is the second-largest in the Scottish Parliament and the second-largest in the Welsh Assembly, the party is organised in the British Overseas Territory of Gibraltar. The Conservative Party traces its origins to a faction, rooted in the 18th century Whig Party and they were known as Independent Whigs, Friends of Mr Pitt, or Pittites. After Pitts death the term Tory came into use and this was an allusion to the Tories, a political grouping that had existed from 1678, but which had no organisational continuity with the Pittite party. From about 1812 on the name Tory was commonly used for the newer party, the term Conservative was suggested as a title for the party by a magazine article by J. Wilson Croker in the Quarterly Review in 1830. The name immediately caught on and was adopted under the aegis of Sir Robert Peel around 1834.
Peel is acknowledged as the founder of the Conservative Party, which he created with the announcement of the Tamworth Manifesto, the term Conservative Party rather than Tory was the dominant usage by 1845. In 1912, the Liberal Unionists merged with the Conservative Party, in Ireland, the Irish Unionist Alliance had been formed in 1891 which merged anti-Home Rule Unionists into one political movement. Its MPs took the Conservative whip at Westminster, and in essence formed the Irish wing of the party until 1922. The Conservatives served with the Liberals in an all-party coalition government during World War I, keohane finds that the Conservatives were bitterly divided before 1914, especially on the issue of Irish Unionism and the experience of three consecutive election losses
London Fire Brigade
The London Fire Brigade is the statutory fire and rescue service for London. It was formed by the Metropolitan Fire Brigade Act of 1865 under the leadership of superintendent Eyre Massey Shaw. Dany Cotton is the Commissioner for Fire and Emergency Planning, which includes the position of Chief Fire Officer, statutory responsibility for the running of the brigade lies with the London Fire and Emergency Planning Authority. In 2013/14 the LFB handled 171,067999 emergency calls, of the calls it actually mobilised to,20,934 were fires, including 10,992 that were of a serious nature, making it one of the busiest fire brigades in the world. In the same 12-month period, it received 3,172 hoax calls, the highest number of any UK fire service, in 2015/16 the LFB received 171,488 emergency calls. These consisted of,20,773 fires,30,066 special service callouts and it conducts emergency planning and performs fire safety inspections and education. He introduced a uniform that, for the first time, included personal protection from the hazards of firefighting.
With 80 firefighters and 13 fire stations, the unit was still a private enterprise, funded by the insurance companies, in 1904 it was renamed as the London Fire Brigade. The LFB moved into a new headquarters built by Higgs and Hill on the Albert Embankment in Lambeth in 1937, during the Second World War the countrys brigades were amalgamated into a single National Fire Service. The separate London Fire Brigade for the County of London was re-established in 1948, in 1986 the Greater London Council was disbanded and a new statutory authority, the London Fire and Civil Defence Authority, was formed to take responsibility for the LFB. The LFCDA was replaced in 2000 by the London Fire and Emergency Planning Authority, at the same time, the Greater London Authority was established to administer the LFEPA and coordinate emergency planning for London. Consisting of the Mayor of London and other elected members, the GLA takes responsibility for the Metropolitan Police Authority, Transport for London, in 2007 the LFB vacated its Lambeth headquarters and moved to a site in Union Street, Southwark.
In the same year, the Department for Communities and Local Government announced that LFB Commissioner Ken Knight had been appointed as the first Chief Fire, Knight was succeeded as Commissioner at that time by Ron Dobson, who served for almost ten years. Dany Cotton took over in 2017, becoming the brigades first female commissioner, dany Cotton is the current commissioner, having taken up the role on 1 January 2017. She holds the Queens Fire Service Medal, frank Jackson, CBE1938 to 1941, Cdr. Sir Aylmer Firebrace, CBE1933 to 1938, Maj. Cyril Morris 1918 to 1933, Arthur Reginald Dyer 1909 to 1918, sir Sampson Sladen 1903 to 1909, RAdm. James de Courcy Hamilton 1896 to 1903, lionel de Latour Wells 1891 to 1896, James Sexton Simmonds 1861 to 1891, Capt. Both divisions were divided into three districts, each under a Superintendent with his headquarters at a superintendent station, the superintendent stations themselves were commanded by District Officers, with the other stations under Station Officers
London, or Greater London, is a region of England which forms the administrative boundaries of London. It is organised into 33 local government districts, the 32 London boroughs, the Greater London Authority, based in Southwark, is responsible for strategic local government across the region and consists of the Mayor of London and the London Assembly. The county of Greater London was created on 1 April 1965 through the London Government Act 1963, Greater London was first established as a sui generis council area under the Greater London Council between 1963 and 1986. The area was re-established as a region in 1994, and the Greater London Authority formed in 2000, the region covers 1,572 km2 and had a population of 8,174,000 at the 2011 census. In 2012, it had the highest GVA per capita in the United Kingdom at £37,232, the Greater London Built-up Area—used in some national statistics—is a measure of the continuous urban area of London, and therefore includes areas outside of the administrative region.
The term Greater London has been and still is used to different areas in governance, history. In terms of ceremonial counties, London is divided into the small City of London, outside the limited boundaries of the City, a variety of arrangements has governed the wider area since 1855, culminating in the creation of the Greater London administrative area in 1965. The Greater London Arterial Road Programme was devised between 1913 and 1916, one of the larger early forms was the Greater London Planning Region, devised in 1927, which occupied 1,856 square miles and included 9 million people. The LCC pressed for an alteration in its boundaries soon after the end of the First World War, noting that within the Metropolitan, a Royal Commission on London Government was set up to consider the issue. The LCC proposed a vast new area for Greater London, with a boundary somewhere between the Metropolitan Police District and the home counties, protests were made at the possibility of including Windsor and Eton in the authority.
The Commission made its report in 1923, rejecting the LCCs scheme, two minority reports favoured change beyond the amalgamation of smaller urban districts, including both smaller borough councils and a central authority for strategic functions. The London Traffic Act 1924 was a result of the Commission, Greater London originally had a two-tier system of local government, with the Greater London Council sharing power with the City of London Corporation and the 32 London Borough councils. The GLC was abolished in 1986 by the Local Government Act 1985 and its functions were devolved to the City Corporation and the London Boroughs, with some functions transferred to central government and joint boards. Greater London was used to form the London region of England in 1994, a referendum held in 1998 established a public will to recreate an upper tier of government to cover the region. The Greater London Authority, London Assembly and the directly elected Mayor of London were created in 2000 by the Greater London Authority Act 1999, in 2000, the outer boundary of the Metropolitan Police District was re-aligned to the Greater London boundary.
The 2000 and 2004 mayoral elections were won by Ken Livingstone, the 2008 and 2012 elections were won by Boris Johnson. The 2016 election was won by Sadiq Khan, Greater London continues to include the most closely associated parts of the Greater London Urban Area and their historic buffers. Thus it includes, in five boroughs, significant parts of the Metropolitan Green Belt which protects designated greenfield land in a way to the citys parks
Ordnance Survey National Grid
The Ordnance Survey National Grid reference system is a system of geographic grid references used in Great Britain, different from using Latitude and Longitude. It is often called British National Grid, the Ordnance Survey devised the national grid reference system, and it is heavily used in their survey data, and in maps based on those surveys. Grid references are commonly quoted in other publications and data sources. The Universal Transverse Mercator coordinate system is used to provide references for worldwide locations. European-wide agencies use UTM when mapping locations, or may use the Military Grid Reference System system, the grid is based on the OSGB36 datum, and was introduced after the retriangulation of 1936–1962. It replaced the previously used Cassini Grid which, up to the end of World War Two, had issued only to the military. The Airy ellipsoid is a regional best fit for Britain, more modern mapping tends to use the GRS80 ellipsoid used by the GPS, the British maps adopt a Transverse Mercator projection with an origin at 49° N, 2° W.
Over the Airy ellipsoid a straight grid, the National Grid, is placed with a new false origin. This false origin is located south-west of the Isles of Scilly, the distortion created between the OS grid and the projection is countered by a scale factor in the longitude to create two lines of longitude with zero distortion rather than one. Grid north and true north are aligned on the 400 km easting of the grid which is 2° W. 2° 0′ 5″ W. OSGB36 was used by Admiralty nautical charts until 2000 after which WGS84 has been used, a geodetic transformation between OSGB36 and other terrestrial reference systems can become quite tedious if attempted manually. The most common transformation is called the Helmert datum transformation, which results in a typical 7 m error from true, the definitive transformation from ETRS89 that is published by the OSGB is called the National Grid Transformation OSTN02. This models the detailed distortions in the 1936–1962 retriangulation, and achieves backwards compatibility in grid coordinates to sub-metre accuracy, the difference between the coordinates on different datums varies from place to place.
The longitude and latitude positions on OSGB36 are the same as for WGS84 at a point in the Atlantic Ocean well to the west of Great Britain. In Cornwall, the WGS84 longitude lines are about 70 metres east of their OSGB36 equivalents, the smallest datum shift is on the west coast of Scotland and the greatest in Kent. But Great Britain has not shrunk by 100+ metres, a point near Lands End now computes to be 27.6 metres closer to a point near Duncansby Head than it did under OSGB36. For the first letter, the grid is divided into squares of size 500 km by 500 km, there are four of these which contain significant land area within Great Britain, S, T, N and H. The O square contains an area of North Yorkshire, almost all of which lies below mean high tide