Senior remain-backing Labour politicians in Manchester have reacted with bemusement after being invited to join the Tory party and elect Boris Johnson their Prime Minister.

Pro-Brexit campaign Leave EU sent out an email this morning with the subject line ‘join the Tories to back a real Brexit leader’.

Featuring a picture of Margaret Thatcher, Johnson and Jacob Rees-Mogg with the message ‘elect a proper Tory leader, click here to join the Conservative party’, it argues there is likely to be a Tory leadership contest within ‘three to six months’.

“After becoming a Conservative Party member, you will be eligible to vote in the final round of that contest,” it adds.

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“You will therefore have a hand in choosing our next Prime Minister - and in determining the kind of Brexit that Britain gets.

“It is not too late to save Brexit or the country.”

The email - part of a renewed campaign by Leave EU founder Arron Banks in response to mounting calls from Remainers for a second referendum - seems to have been sent to some unlikely recipients, however, including members of Manchester council’s Remain-backing Labour executive.

Deputy council leader Sue Murphy said the missive, which seeks to highlight rifts within the Conservative Party to argue Theresa May will soon be ousted, only showed ‘how split the Tories are’.

But she added: “Leave EU need better data - I don’t think I’m exactly their target audience for this.

“Still, I suppose Arron Banks has got money to waste on his personal agenda.”

The email pushes Brexiteers to sign up to the Conservative party en masse in order to ensure that whoever replaces Theresa May pursues a hard Brexit in the coming months.

(Image: PA)

It comes amid concerns from some Tory MPs, including prominent Remainer Anna Soubry, that the move will amount to ‘entryism’ - leading the party to be flooded by new pro-Brexit members specifically joining up just to swing any imminent leadership contest.

Leave EU’s message tells ‘supporters’ on its mailing list: “You can help to achieve the clean Brexit this country voted for by backing a Brexit candidate in any future leadership election.

“But the clock is ticking. Every second counts.”

Underneath the picture of Thatcher, Johnson and Rees-Mogg it tells recipients, including baffled Labour members: “We want people to join the Conservative Party, attend local meetings, and then push for fundamental change within the party.”

It argues Labour is set to split thanks to its own internal divisions, leaving behind a centrist party that will ‘split the left’ and leave a ‘once in a lifetime opportunity for the Conservative Party’.

Beneath a picture of Boris Johnson bearing the message ‘click here to join the Tories and back a proper leader’, it adds: “Watch this spot as we start the “Conservative Grassroots Mutiny” campaign.”