Jeremy Corbyn and Jon Trickett, the Labour MP, met the head of the civil service today to call for an inquiry into reports that senior civil servants said that the Labour leader was “too frail” to be prime minister Stefan Rousseau/pa

Jeremy Corbyn has taken the Labour Party to its lowest level of support in polling history, with fewer than one in five voters planning to back him at the next election, according to a survey.

Labour are fourth for the first time, with only 18 per cent saying that they would vote for the party if an election were held today, the Times/YouGov poll shows.

The only previous occasion when Labour have scored 18 per cent since polling began in the 1940s was in May 2009 as Gordon Brown’s government grappled with the financial crisis.

Labour have fallen two points since last week, a drop in support that will intensify doubts among the party’s MPs about Mr Corbyn’s leadership. It bolsters claims that his Brexit…