The Press and Journal can reveal north-east businessman Stewart Spence is backing Conservative Ross Thomson for Aberdeen South in the general election.
A long-time SNP supporter, the Marcliffe Hotel owner is a friend of former first minister Alex Salmond and endorsed Callum McCaig in 2015 when he won the seat.
But he has switched his allegiance after leading the revolt against business rates rises earlier this year.
He said Mr Thomson had been a “strong voice” for the business community “at a time when local companies are being hammered by increases in rates”.
He added: “We need a strong voice in government at Westminster to speak up for businesses in this area, and I am happy to support Ross in this election.”
Jim Milne, managing director of oil and gas services company Balmoral Engineering, and Eric Shearer, managing partner at Knight Frank, are also backing the Tory candidate.
Mr Thomson argued their support was “another sign of a shift away from the SNP in this part of the country”.
He added: “Aberdeen is not getting a fair deal from the Scottish Government and we had to fight tooth and nail to persuade Derek Mackay to take action on business rates.”
An SNP spokesman said Mr McCaig, who is standing again, was delighted to have the “best wishes” of the hotelier as the party’s candidate.
He added: “We’re also extremely grateful for his generous contribution to Alex Salmond’s campaign in Gordon.
“Ross Thomson is being entirely disingenuous over business rates. While the SNP in government has taken swift action to address legitimate concerns from north-east businesses, he failed twice to vote for rates relief schemes – both as an MSP and as a local councillor.”
The contribution referred to is money raised from a Marcliffe auction prize.
A Tory source said the party had auctioned off similar prizes donated by Mr Spence at its annual north-east conference.
The businessman confirmed he was making a contribution to each party because he was “desperate for them to work together”.
He added: “This is the only way we are going to get out of the mess Aberdeen is in.”
Among those supporting Mr McCaig are Kenny Anderson, managing director of Anderson Construction, and Gary Atkinson, owner of Carmelite Hotel.
Mr Anderson called him a “fantastic ambassador for Aberdeen and local businesses”.
Mr Atkinson added: “Callum is exactly the sort of person we need fighting Aberdeen’s corner.”
The other candidates in the constituency are Jenny Wilson for the Liberal Democrats and Labour’s Callum O’Dwyer.