Infighting over Brexit has made it difficult for Theresa May to stamp her agenda on the Conservative Party

The prime minister is facing a donors’ revolt and growing pressure to leave Downing Street as soon as the outline of a trade deal is negotiated with the European Union this autumn.

Discontent with Theresa May among the Conservatives’ financial backers boiled over at a fundraising event last Thursday, according to a donor. An account of the event — where about a quarter of the 50 donors present were said to have demanded her resignation — has been circulating among Brexit-supporting Tory MPs.

Mrs May’s grip on No 10 has weakened markedly in recent days as the Leave and Remain wings of her party raise the stakes before the start of talks on Britain’s future relationship with the EU. Dismay over political drift, concerns