Mayor of London Boris Johnson may be mumbling and grumbling over how he will cast his vote at the EU referendum, but around 80 MPs have already made their pro-Brexit positions clear.
The parliamentarians include Ukip's only MP Douglas Carswell, top Labour Eurosceptic Kate Hoey and a former Europe minister, Conservative MP David Davis.
The list of representatives backing a 'leave' vote will most likely grow once David Cameron has secured a renegotiation deal from Brussels and ministers are allowed to publicly campaign for a Brexit.
Chris Grayling, the leader of the House of Commons, has already signalled his support for a breakaway from the EU.
Work and pensions secretary Iain Duncan Smith is expected to join Grayling as well as employment minister Priti Patel, a rising star of the Conservative Party who was tipped by the Mail on Sunday as the leader of the Brexit campaign.
Northern Ireland secretary Theresa Villiers and culture secretary John Whittingdale are two other cabinet ministers thought to be behind 'leave'. Further speculation has surrounded the positions of justice secretary Michael Gove and business secretary Sajid Javid.
The top Tories have made Eurosceptic soundings in the past and one of Gove's former top aides, Dominic Cummings, is the campaigns director for Vote Leave. Only six Labour MPs have declared for 'leave', but German-born Gisela Stuart said she was drifting toward a pro-Brexit position when she appeared on BBC One's Andrew Marr show on 14 February.
A source close to the Labour Leave campaign has also previously told IBTimes UK that the group expects more support from MPs.
Elsewhere, Sammy Wilson has publicly backed a Brexit, while his Democratic Unionist Party colleagues, including Nigel Dodds, are also expected to take a Eurosceptic position.
It is not currently clear how the two Ulster Unionist Party MPs will campaign, but a source close to Tom Elliot told IBTimes UK that the parliamentarians could adopt a "soft 'yes'" position.
Full list of MPs backing a Brexit (updated throughout the campaign)
More about the EU referendum