A Liberal Democrat candidate has quit his party with a broadside against the "betrayal" of coalition with the Conservatives.
Hugh O'Donnell has served for four years in the Scottish Parliament and was the leading candidate in the party's Central Scotland list with just over five weeks until the Holyrood election.
According to a recent ICM poll, the party is running fourth with 10% support in constituencies and 9% in regions before the May 5 poll.
Mr O'Donnell, who will now stand as an independent candidate in the region, explained his decision in an article in the Scottish Mail on Sunday.
He criticised the party's Scottish leader Tavish Scott and said founding principles have been "subsumed" by a desire for position and power.
Leadership cannot be regarded as "either Liberal of Democratic", he said.
Mr O'Donnell added: "The greatest betrayal of all, of course, is the alliance formed in London between the Lib Dems and the Tories."
In Scotland, the Lib Dems were a junior partner in a Labour-led administration for eight years after devolution in 1999. The SNP formed a minority government at the 2007 election and go into this year's election closely behind leaders Labour, according to recent polls.
Mr O'Donnell said he and his colleagues had been told not to air grievances about the Westminster coalition.
He added: "Since that fateful day, I have watched helplessly from the sidelines as this Government at Westminster has attacked every vulnerable group in Scotland, from carers to disabled students to migrants, with some of the most draconian policies I have ever seen in the name of cuts.
"Not a word of criticism from the party leadership in Scotland has been uttered - even though the contempt shown for Scotland and, indeed, the federal structure of the party knows no bounds."
Mr O'Donnell is also unhappy at the decision to hold a referendum on whether the Alternative Vote should replace traditional first-past-the-post for Westminster elections on the same day as the Scottish parliamentary election.
He complained that the party at Holyrood had voted tactically instead of on principle over controversial subjects such as the SNP's proposed minimum price for alcohol - a policy which failed to win enough support to progress last year.
He continued: "I have fought the leadership as hard as I could, but I am just too tired to do it any more.
"This is not the same party I joined, full of enthusiasm, all those years ago.
"I can no longer be party to the control freakery, the 'image is everything' attitude, and the dictatorial style of doing things.
"It is a party I no longer want to be part of and neither should other principled Liberals."
A Liberal Democrat spokeswoman announced Mr O'Donnell's departure yesterday, adding: "We have accepted Hugh O'Donnell's resignation."
Labour's Scottish leader Iain Gray said: "It is not just Mr O'Donnell who's been betrayed - people who voted Lib Dem right across Scotland have been betrayed. Not a single person in Scotland voted Lib Dem to get a Tory government."
Christine Grahame, SNP candidate for Midlothian South, Tweeddale and Lauderdale, said: "Minimum pricing and giving the people a right to choose Scotland's future are issues which should be above party politics. Lib Dem supporters have backed these ideas, only to be slapped down by the party leadership."
Jeremy Purvis, the Lib Dem candidate for Midlothian South, Tweeddale and Lauderdale, said he is disappointed by the decision.
Mr Purvis, who is also the party's finance spokesman, told the BBC's Politics Show: "Hugh's made his decision, I'm disappointed by that. I don't think it's representative with the rest of the party.
"We had a very upbeat spring conference. In my own area we've been recruiting new members and new supporters."