In an Opinium poll in the Observer, focused on this month's European elections, Nigel Farage's new party is predicted to hoover up 34 per cent of the vote. The same poll gave Labour 21 per cent and put the Tories in a miserable fourth place with 11 per cent

But an even more extraordinary poll, commissioned by a Brexit Party donor and published in the Sunday Telegraph, said for the first time the Brexit Party would beat the Tories in a General Election.

The ComRes survey of voting intentions put Brexit on 21 per cent to the Conservatives' 20, which would see Farage's team win 49 seats, becoming the UK's second biggest party after Labour, with 137. 

Andrew Hawkins, the chairman of ComRes, described the poll as a 'disaster', adding: 'If the Conservative leadership contenders are not careful, there will be no party for them to lead.'

It will deepen the panic spreading among Tory members, as more than 600 Tory association chairmen, councillors, donors and activists, wrote to the Telegraph to warn that if Mrs May cannot deliver a clean exit, MPs must replace her urgently or 'risk disaster'.