Elliott was the founder and has served as chief executive of the TaxPayers' Alliance in 2004, Big Brother Watch and Business for Britain.

[4] Elliott served as press officer for the European Foundation from 2000, and political secretary to Timothy Kirkhope MEP from 2001.

[citation needed] In 2009, he founded the civil liberties and privacy pressure group Big Brother Watch, in response to "the prevailing climate of authoritarian and intrusive policies being pursued by the British state".

[10] In an article for the New Statesman, Elliot said he attended a Conservative Friends of Russia reception in 2012 and a 10-day trip to the country, but claimed he had no further involvement.

'[2] In October 2015, Elliott became the chief executive of Vote Leave, a cross-party organisation formed to campaign for Brexit, the withdrawal of the United Kingdom from the European Union.

The organisation managed to recruit the support of a number of high-profile politicians, including Conservative MPs Boris Johnson and Michael Gove, who became key figureheads.

[19] Elliott was portrayed by actor John Heffernan in the HBO- and Channel 4-produced drama, Brexit: The Uncivil War (2019).