Johnson told the rally: “You know the most depressing thing about the campaign to Bremain? It is that there is not a shred of idealism.

“Not a single one of them will stand up and admit that it is political. No one will say: ‘You know what, I love the idea of a federal Europe’, because that is the true logic of their position.

“But that is not what they say – oh no. They keep saying that they are Eurosceptics, but we have no choice. We agree with you about the democratic problem, they say – but it’s the price we have to pay.”

Jeremy Corbyn has been forced to abandon plans to give a speech calling for all Turkish citizens to gain access to the UK amid fears that it could push Britain out of the European Union.

Senior Labour party sources told this newspaper that Mr Corbyn had planned a major intervention this month in Istanbul calling for Turkey to join the EU, allowing it's 75 million people access to Britain under freedom of movement rules.

Sources inside the leader's office are understood to have intervened to get the speech scrapped, triggering a furious row.