Andrew Paul Gilligan is a British policy adviser, and former transport adviser to Boris Johnson both as Mayor of London and as Prime Minister. Until July 2019, he was senior correspondent of The Sunday Times and had also served as head of the Capital City Foundation at Policy Exchange. Between 2013 and 2016 he also worked as the Mayor's cycling commissioner for London, and in 2020 he was an appointee of Central Government to TfL's Board. He is best known for a 2003 report on BBC Radio 4's Today programme in which he described a British government briefing paper on Iraq and weapons of mass destruction as having been "transformed in the week before it was published to make it sexier". This change became widely known, in the words of newspaper headlines about the story, as being "sexed up".

The mayor of London is the chief executive of the Greater London Authority. The role was created in 2000 after the Greater London devolution referendum in 1998, and was the first directly elected mayor in the United Kingdom.