Theresa May has privately vowed to thwart any attempt by
Boris Johnson to take the UK out of the EU without a deal, her allies have told The Mail on Sunday.
The disclosure comes as senior party figures told The Mail on Sunday that Mrs May had voted for ultra-Remainer Rory Stewart in Thursday's ballot of MPs, which led to a landslide victory for Mr Johnson.
Mrs May, who has vowed to stay on as an MP after she leaves Downing Street next month, has suggested she would join forces with pro-Remain Ministers such as Chancellor
Philip Hammond and Pensions Secretary Amber Rudd to try to stop Mr Johnson from leaving after the October 31 deadline 'Deal or No Deal'.