A former senior figure in the Scottish National Party has backed calls for John Swinney to stand down as the party leader.
Jim Sillars said devolution has damaged the Nationalists
Jim Sillars, who was both an MP and deputy leader of the Nationalists in the 1990s, said it was time for a change at the top.
He also told BBC Radio Scotland's Sunday Live programme that devolution had proved to be a disaster.
Mr Sillars said the independence campaign was being sidelined.
The former Glasgow Govan MP said the Scottish National Party faced deep-seated problems and the prospect of disaster at the next General Election.
He added that a "leathering" at the polls could be a wake-up call for the party.
He said: "It's not just John Swinney. Party democracy has gone and with it party membership has gone.
"We are now in the position, unless there is an acceptance by the leadership that they have led the party in the wrong direction for a considerable period of time, then I fear the events of the General Election of next year."
Mr Sillars said the party's acceptance of devolution had been a tactical blunder.
He said: "Devolution has parochialised Scottish politics and marginalised Scotland at Westminster.
"I would challenge any of your listeners. Turn to your partner, wife, friend and say 'name me 12 Westminster members of parliament' and they'll be hard pushed to do that.
"Not because they're dummies, but the Scottish media hardly gives them any coverage from a Westminster point of view, so the people in the big league, they don't really count.
John Swinney has survived one leadership challenge
"Instead of that we get all the attention on a parliament at Holyrood which is a spending parliament only, constrained by a single budget and really has no influence on the wealth creation part of Scottish life and the Scottish economy."
Mr Sillars said that recommending former leadership candidate Alex Neil as a possible successor could have a negative result.
He said: "My problem is, if I say I think Alex Neil would make the best leader, then I damn Alex Neil because that is what happened last time - he was damned by his previous long-term association with me."
However, former MSP Kenny Gibson defended the leader and said he had tried to unite the party.
He said: "I lost my seat in the Scottish Parliament last year, but I certainly don't blame John Swinney for that.
"The SNP had a manifesto that was agreed some months in advance, it was put together on a collective basis, and if the SNP failed, then the SNP failed collectively - it did not fail because of one man.
"The people who are trying to undermine John Swinney should stop moaning and groaning.
"They should either support John or in my view they should simply go and join another political party because they are certainly not advancing the independence cause."
Last week, former MSP Gil Paterson called on Mr Swinney to resign.
The public criticism of Mr Swinney's leadership came after a poor showing in the European Elections.
Mr Paterson said there were others in the party who could lead, including former leader Alex Salmond.
Mr Swinney saw off a leadership challenge from Glasgow activist Dr Bill Wilson at the party's conference in Inverness last year.