The list MSP for the South of Scotland ran in the leadership contest to replace Ruth Davidson after she stood down as party leader in August last year, claiming she was running to ensure there was no “coronation" of favourite Jackson Carlaw.
She promised to “kick-start a blue-collar revolution”. However, she lost heavily to Mr Carlaw, who was elected in February this year – though he stood down in July after coming to the conclusion he was “not the person best placed” to lead his party into the 2021 Scottish Parliament elections.
He was replaced by Moray MP Douglas Ross, with Ms Davidson returning to a Holyrood frontbench role to lead the Scottish Tories in Holyrood.
Michelle Ballantyne, who began her political career as a Tory councillor in the Scottish Borders Council, said: “It is with great sadness that I have decided to resign today from the Scottish Conservative and Unionist Party.
“That said, I recognise and respect the work Douglas, Ruth and their team are putting in to re-shape the future of the Scottish Conservatives and the party’s position going forward.
"However, as Douglas indicated in his address to our party conference, there are differences arising for some in the party’s positioning on policy and, indeed, its principles. Sadly, for me, this means I no longer feel that the party and I are a good fit.
“I have not taken this decision lightly and I wish both Douglas and Ruth, as well as all my colleagues, the very best going forward.”
She added: ”I’m looking forward to continuing to represent my constituents across South Scotland as an independent MSP and champion local issues at Holyrood. While I may be leaving the Scottish Conservatives, I am not leaving the Scottish Parliament and my door remains open, as always, to my constituents.”
In a joint statement, Mr Ross and Ms Davidson said: “We would both like to thank Michelle for her service to the Scottish Conservatives down the years. As well as her time on Scottish Borders Council and in the Parliament, she has also been an active member of the voluntary party. We wish her well for the future.”