THE Yes campaign suffered another blow yesterday when the independent MSP Margo MacDonald denounced its tactics and urged Alex Salmond to drop any plans for supporting a devo-max question on the referendum ballot paper.

As Yes Scotland announced its eight-member leadership board – to include Deputy First Minister Nicola Sturgeon, actress Elaine C Smith and restaurateur Andrew Fairlie – it was suggested Ms MacDonald had been approached to become vice-convener but turned down the role.

The MSP, who previously claimed the Yes campaign had become too heavily aligned to the SNP, said it had failed to engage voters.

"It's got no shape, no boundaries, no premise," she said. "In short, I don't think we've had a debate, I think we have had a lot of noise."

On the issue of the second "more powers" option, she urged the First Minister to abandon it, arguing that if such a proposition were put forward then not only Scots should have a say but those in England, too.

"Ditch the second question because you can't deliver it," she said.

"The only thing you can deliver is independence."

Last night, Scottish Labour said Ms MacDonald's intervention would be a "hammer blow" to the Yes campaign. "There is now growing consensus that there should be one, straighforward question," said Patricia Ferguson, external affairs spokeswoman.

Ruth Davidson, the Scottish Conservative leader, dismissed Yes Scotland's announcement as a "diversionary tactic" designed to disguise how the campaign could not answer legitimate questions about Scotland breaking away from the UK.