Field Marshal John Campbell, 2nd Duke of Argyll, 1st Duke of Greenwich,, styled Lord Lorne from 1680 to 1703, was a Scottish nobleman and senior commander in the British Army. He served on the continent in the Nine Years' War and fought at the Siege of Kaiserswerth during the War of the Spanish Succession. He then went on to serve as a brigade commander during the later battles of the War of the Spanish Succession, and was subsequently given command of all British forces in Spain at the instigation of the Harley Ministry. After conducting a successful evacuation of the troops from Spain, he became Commander-in-Chief, Scotland. During the Jacobite Rebellion, he led the government army against the Jacobite forces led by the Earl of Mar at the Battle of Sheriffmuir. Afterwards he served as Lord Steward and then Master-General of the Ordnance under the Walpole–Townshend Ministry.

Field marshal (FM) has been the highest rank in the British Army since 1736. A five-star rank with NATO code OF-10, it is equivalent to an Admiral of the Fleet in the Royal Navy or a Marshal of the Royal Air Force in the Royal Air Force (RAF). A Field Marshal's insignia consists of two crossed batons surrounded by yellow leaves below the Tudor Crown. Like Marshals of the Royal Air Force and Admirals of the Fleet, Field Marshals traditionally remain officers for life, though on half-pay when not in an appointment or retired. The rank has been used sporadically throughout its history, and was vacant during parts of the 18th and 19th centuries. After the Second World War, it became standard practice to appoint the Chief of the Imperial General Staff to the rank on his last day in the post. Army officers occupying the post of Chief of the Defence Staff, the professional head of all the British Armed Forces, were usually promoted to the rank upon their appointment.