George Galloway has announced that he will stand for Mayor of London in 2016.

The Respect Party leader lost his seat in the House of Commons to Labour in the general election earlier this month.

Declaring himself as a candidate on Twitter, he wrote “I'm standing for Mayor of London 2016” and urged supporters to get in touch to help with his campaign.

George Galloway will attempt to replace Boris Johnson next year (Getty)

It had long been rumoured that Mr Galloway would attempt to replace Boris Johnson, who is currently both Mayor and the Tory MP for Uxbridge and South Ruislip.

He appeared to confirm his candidacy in April, telling Sky News: “I won't run for London Mayor if I am re-elected on 7 May. If I am not re-elected I will run.”

Mr Galloway will be facing competition from all sides of the political spectrum, including from Labour’s Tessa Jowell, who launched her campaign with a pledge to build 2,000 affordable homes a year in the capital.

The former culture secretary has been nominated by sixteen of the local London Labour parties to declare so far, while Tooting MP Sadiq Khan is in second place with 12.

Dame Tessa unveiled her campaign in Brixton (Tessa for Londoners/PA Wire)

London MPs David Lammy, Diane Abbott and Gareth Thomas are among the other Labour candidates running.

Four Conservative hopefuls are looking to succeed Mr Johnson, most famously former England football player Sol Campbell.

Assembly members Andrew Boff and Stephen Greenhalgh could also run for the Tories, as well as Ivan Massow.