Breaking up the Scottish Conservatives would be the “greatest political error” since the Jacobite retreat during the 1745 rebellion, a Tory grandee has claimed.
Former Scottish Secretary Lord Forsyth spoke after leadership hopeful Murdo Fraser revealed details of his plan to split from the UK Conservatives.
Mr Fraser believes the Tory brand has become “contaminated” in Scotland and only a break can return centre-right politics to the levels of support enjoyed in the 1950s.
The proposal has divided the Conservative membership in Scotland and dominated debate in the run-up to the party electing a successor to Annabel Goldie.
Lord Forsyth, who is backing Glasgow list MSP Ruth Davidson for leader, attacked the plan.
“Harping back to the halcyon days of the ’50s when Scottish Conservatives had 50% of the vote is misleading and misguided,” he said. “There were only two candidates in most constituencies, there were no credible SNP candidates, and the mere handful of Liberal Unionists supported the Tories.
“Scottish Conservatives can only rebuild their fortunes by fighting in Scotland with conviction and determination.”
Referring to the events of December 1745, he added: “Abandoning our party now would be the greatest political error since Bonnie Prince Charlie, on the advice of faint-hearts, turned back at Derby to face certain defeat.
“It would condemn the Scottish Tories to years of internal constitution wrangling when it is our duty to fight to preserve the United Kingdom and Scotland’s future prosperity.”
Ms Davidson is 11-10 favourite to win the four-horse leadership race with bookmaker Stan James, ahead of Mr Fraser at 6-5.
“I want to bring our party together, not rip it apart,” she said. “I am proud to serve my party the Scottish Conservative and Unionist Party and I believe that with the right leader we can reinvigorate the party and build a decade of success…
“I believe I am that leader and I will fight for a united party in our United Kingdom.”
Mr Fraser’s campaign manager, Mid Scotland and Fife MSP Liz Smith, defended the proposal and warned party members to avoid name-calling.
And Mr Fraser added: “All over the country, the momentum in favour of our transformation into a new, progressive, distinctly Scottish centre-right party is growing quickly.
“For the first time in decades our members are hearing a proposal to turn us from being a party which loses all the time into one which starts to win.”
He revealed the new party would still take the Conservative whip at Westminster, attend its conferences and invite Prime Minister David Cameron to theirs.
Former Conservative Scottish Secretary Sir Malcolm Rifkind has backed the plan.
Transport spokesman Jackson Carlaw and Central Scotland MSP Margaret Mitchell are also standing for leadership.