BORIS Johnson’s Scottish campaign manager for the 2019 general election has joined the campaign to elect Liz Truss as Tory leader and Prime Minister.

Ross Thomson, a fomer Conservative MP and MSP, who is an enthusiastic Brexiteer, was among the most prominent supporters of Mr Johnson north of the Border, criticising fellow Scots Tories for attacks on him.

To date most senior Scottish Conservatives, who have publicly declared who they will vote for, have backed Ms Truss's rival former Chancellor Rishi Sunak.

No MP or MSP has yet to favour the Foreign Secretarty in the contest.

Mr Thomson stood down as the Scottish conservative candidate for Aberdeen South in 2019, the seat he had won at the 2017 election, after being accused of groping Labour MP Paul Sweeney in a a Commons bar.

He had denied any wrongdoing and was later cleared of any breach of parliament’s misconduct policy by the parliamentary commissioner for standards who concluded that Mr Thomson’s behaviour was not sexual in nature. 

Mr Sweeney, who represented Glasgow North East, was later among six Scottish Labour MPs who lost their seats in the December 2019 general election with the party left with just a single MP, Ian Murray, north of the Border.

Liz Truss's team today confirmed that Mr Thomson had joined their campaign as a supporter but would not comment on whether he was advising on Scotland and the Union.

Ahead of the Conservative conference in 2018, senior Scottish Tories launched a bid - dubbed 'Operation Arse' - to stop Mr Johnson from succeeding Theresa May amid fears it could kill off the party's revival north of the Border.

But Mr Thomson hit back, launching an outspoken attack on critics of the then Foreign Secretary.

Mr Johnson's speech to the conference in Birmingham was seen by many in the party as a bid for leadership of the party, which has been criticised from many quarters including the Scottish Conservative leader Ruth Davidson and Scottish Secretary David Mundell.

But in a Twitter rant Mr Thomson, who flanked Johnson on his way through the media scrum, labelled the critics ”Operation Arsehole’s” [sp].

Mr Johnson had received a rapturous reception as he attacked May's Brexit strategy hammered out at her Chequers residence and set out his alternative.

"Regardless of your view of Boris Johnson, 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," Mr Thomson wrote on Twitter.

The row came after Mr Mundell told a conference fringe event that Mr Johnson was “not an asset” to the Tories.

He 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.

"I think 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."

Mr Thomson also backed Michelle Ballantyne against Jackson Carlaw in the Scottish Conservative leadership race in 2020, won by Mr Carlaw.