Emmanuel Macron blamed Brexit for the small boat migrant crisis as he stood beside Sir Keir Starmer last week. The French president said the British people had been “sold a lie”, but his claim has been described as “idiocy”.

Academic Matthew Goodwin explained that the problem of unlawful migration began long before the UK left the EU in 2020 and has been growing for 15 years. Mr Goodwin, a former professor of politics in the School of Politics and International Relations at the University of Kent, said Mr Macron’s argument “though popular in Brussels, Oxford and Cambridge, is idiocy”. Writing on his Substack, he said: “The small boats crisis began long before Britain left the EU and Brexit has nothing to do with why a similar invasion has been unfolding across the EU for 15 years.”

And he criticised the idea that it was easier for the UK to remove asylum seekers when we were in the EU. He said: “Even when Britain was a member of the EU, under the so-called Dublin convention, we hardly sent back any illegal migrants or asylum seekers, while European courts routinely got in the way of these efforts to return migrants.

“In fact, when we were in the EU, we often took more migrants than we sent back, which I suspect will now happen again through Starmer’s gimmick.”

He added: “And what Starmer and Macron are not telling you is that if we were still in the EU, we would currently be under enormous pressure to ‘share the burden’ by taking in yet more asylum seekers through the EU migration and asylum pact.

“They are, once again, gaslighting you, treating you like morons.”

Mr Goodwin also criticised the “one in, one out” deal agreed between the EU and France, which will allow the UK to send some small boat migrants back to France in return for accepting an equal number of asylum seekers with a link to the UK, such as those with relatives here.

He said: “The British people do not want ‘one in, one out’. They want ‘none in, all out’.”