Douglas Ross has denied giving himself “job insurance” by choosing to stay on as an MSP if he fails to be elected at Westminster.
Mr Ross announced on Monday he would stand down as leader of the Scottish Conservatives after the UK general election.
However, he will only resign his Highlands and Islands Holyrood seat if he is elected as MP for Aberdeenshire North and Moray East, where he has controversially replaced David Duguid as a candidate.
Mr Ross said he had “listened to the concerns of colleagues” but said he did not feel his decision made it appear Holyrood was “less important” than Westminster.
Mr Duguid has disputed suggestions he is “seriously ill” and had been adopted as a candidate by local party members before he was, in effect, deselected by the Scottish Conservative management board.
Mr Ross then announced his intention to stand in the constituency last week, reversing his previous plans to stand down as an MP.
The seat, recently redrawn as Aberdeenshire North and Moray East, was held under the title of Banff and Buchan by Mr Duguid since 2017.
Mr Ross said it was “not feasible” for him to continue serving in two parliaments, as well as maintaining his roles as party leader and a Scottish football assistant referee.
He said he had spoken to prime minister Rishi Sunak about his decision yesterday.
He insisted he had not been asked to stand down as leader by colleagues at Holyrood and denied giving himself a fall back if his bid to become an MP fails.
“I have listened to concerns from colleagues that they want the leader of the Scottish Conservatives to be based in Holyrood,” he told BBC Radio’s Good Morning Scotland.
“I’m absolutely not saying that [Holyrood is less important than Westminster]. The two parliaments deal with very different things.
“I think the back benches of Holyrood have got a number of former leaders on them and there are ex-leaders of every political party sitting on the back benches at Holyrood. Some making more contribution to others and I think I have shown that I will champion local issues.”
Mr Ross is also under pressure over reports by the Sunday Mail that his advisers had raised concerns over a series of travel claims, with suggestions they may have been related to his work as a top-level football linesman.
The newspaper highlighted 28 travel expense requests for flights between London and Edinburgh and Glasgow.
Under UK parliamentary rules, MPs can only claim for travel from their home airport. Moray does not have an airport, but Mr Ross could have claimed for flights to Aberdeen or Inverness.
Mr Ross said the expenses were approved by independent parliamentary body IPSA and he would have “no issue” with the expenses being examined for a second time.
Mr Ross said he stood by the expense claims, adding he was “very comfortable” with IPSA reviewing them.
He said: “I put out a statement saying all of my expenses were incurred as a result of my activities in parliament and getting to and from Westminster.
“I’m very comfortable with the IPSA review.
“I’ve quite often had to fly from different airports depending on what is happening. With local circumstances, with availability in flights. There is no stipulation you have to have a home airport.”
He added: “It is for others to defend their own actions. I’m being very open and honest about my situation.”
First minister John Swinney described the allegations as “significant and serious” and called on Mr Ross to explain.
He said the allegations could amount to a “potential misuse of public funds”.
The party has called on Mr Ross to make a statement in the Scottish Parliament.
Meanwhile, Scottish Labour’s deputy leader, Jackie Baillie, said: Voters know that this rotten Tory government has nothing to offer Scotland.
“It’s no wonder Douglas Ross has given up on trying to resuscitate the Scottish Tories’ flailing campaign.”
Mr Ross visited the King’s Theatre in Edinburgh on Tuesday morning, prior to the BBC Scotland leaders’ debate.
The 100-year-old building is undergoing a renovation supported in part by the UK government’s community ownership fund.
It is part of the Conservative government’s levelling-up project, which Mr Ross claimed had been “a game-changing success story for communities up and down Scotland”.
He said: “Levelling up has funded countless projects that otherwise would never have got off the ground because Scotland’s local authorities – which can barely sustain lifeline services due to SNP government cuts – could never afford them.”