CONSERVATIVE disunity over Boris Johnson’s bid for the party leadership has been laid bare with one Scottish Tory MP branding colleagues trying to stop the former Foreign Secretary becoming Prime Minister “arseholes”.

Ross Thomson, who represents Aberdeen South, launched his outspoken attack following Mr Johnson’s tub-thumping speech at a fringe event at the Conservative Party conference in Birmingham.

The address, in which the former Cabinet minister denounced Theresa May’s Chequers Plan a constitutional outrage, came in the wake of a Stop Boris campaign launched by senior Scottish Conservatives - dubbed 'Operation Arse' – who fear a Johnson premiership would kill off Ruth Davidson’s bid to become First Minister at the 2021 Holyrood election.

But Mr Thomson, an ardent supporter of Mr Johnson and one of those who flanked him as he made his entrance to speak at the fringe event, lashed out at his Scottish colleagues in a late-night Twitter comment.

He wrote: “Regardless of your view of @BorisJohnson, today in his characteristic style he injected some much-needed energy, optimism, passion and enthusiasm to a flat conference.

“The reaction in the hall was electric which even those “Operation Arsehole’s” can’t deny. #ChuckChequers #CPC18"

The row blew up after David Mundell publicly hit out at Mr Johnson, saying he was “not an asset” to the party.

The Scottish Secretary said: "Unfortunately, Mr Johnson seems to behave in a way that suggests he is only focused on his own self-interest and not on the interests of our country and I find that very disappointing.

"What is a fact is that Mr Johnson is not an asset for the Scottish Conservative Party. I don't think people find that his behaviour is one that would endear him to voters.

"We have a very, very strong leader in Scotland in Ruth Davidson who had a very significant contribution to make to this conference. Her message was to rally round the prime minister as we move forward with Brexit."

One Tory MP said a Johnson premiership would be a “nightmare” for Ms Davidson, a Remainer, who would have to endure the attacks from the SNP and Scottish Labour as her UK leader pursued a hard Brexit.