Theresa May odds-on not to last out the year as prime minister

Theresa May is odds-on not to be prime minister by the end of the year after a dramatic day of ministerial resignations triggered by the departure of former Brexit Secretary Dominic Raab.

May thought she had won unanimous cabinet approval for her EU deal but it was left in tatters after Raab and former Work and Pensions secretary Esther McVey resigned from their posts and several junior ministers swiftly followed suit.

Attention quickly switched to a possible leadership challenge with leading Brexiteer Jacob Rees-Mogg among MPs who wrote letters of no confidence in the prime minister to Graham Brady – chairman of the Conservative backbench 1922 Committee.

Forty-eight signatures are required to trigger a vote of no confidence among Conservative MPs but May's position appears vulnerable.

She is as short 8-13 to leave number ten this year and best at 4-5. May is 13-8 to exit in 2019 and 10-1 to stay until 2020 or later.

For now May faces the twin struggles of trying to resist a leadership challenge and attempting to get a Brexit deal through parliament.

However, the chances of 'no deal' appear to be increasing and there has been market support for a second EU referendum which is 7-4 to take place and 1-2 not to.

Potential leadership challengers could include Raab, who is the narrow 6-1 favourite to be the next Conservative leader. Home secretary Sajid Javid and Boris Johnson are 7-1.

A new leader might feel the need to seek a mandate and the chances of an imminent general election are on the rise with Betfair and Paddy Power going odds-on that a national poll will take place in 2019.

The outcome of a future general election looks tight with Conservatives 10-11 to win the most seats and Labour 11-10. Labour leader Jeremy Corbyn is the narrow favourite in the next prime minister betting in a wide-open market at 5-1.