THE commission tasked with brokering a quick deal on Scottish devolution could face calls for a suspension to head off "a very bad botch job", academics and MPs have warned.

It came as Lord Smith of Kelvin, who is chairing the group tasked with producing recommendations on more devolution said his target is not "mission impossible" despite its tight deadlines

The Smith Commission on Scottish devolution is the worst possible forum for constitutional change and is unlikely to emerge with a sustainable solution, MPs have heard.

Tory MP Christopher Chope questioned whether people should rely on the "so-called" devolution vow, as it was given without the UK Parliament's consent and dismissed as salesman's puff by nationalists.

A former Northern Ireland deputy first minister warned deals and deadlines brokered during the Good Friday Agreement led to implementation failure, stalling and frustration.

Graham Allan, convener of the Political and Constitutional Reform Committee, warned there was a feeling arising in some quarters that the commission should be suspended.

But Scottish Labour chief whip Lewis Macdonald said the powers must be delivered at the pace promised before the referendum.

Professor Michael Keating, director of the Scottish Centre on Constitutional Change, told the committee: "Frankly, I think the timetable that we have been given to do this is not realistic."

He added: "I'm not talking about stringing this out indefinitely and having endless discussion, but at least a year seems to be a reasonable time to put together something that will work and get the technical details right so that it won't unravel and have to be turned to again."

Professor Nicola McEwen, associate director at the Scottish Centre on Constitutional Change, replied: "No, we are in a political context where there is an election round the corner and these create imperatives which mean, I think, that the timetable is not about to be changed.

"I suspect that means whatever comes out is probably not going to be sustainable and we will be back here within a few years talking about either fixing that or 'what next?'."

She continued: "This is not even a convention or a commission where you have got experts and representatives in a room trying to think through and reflect on the issues.

"It's not that at all, it's trying to find agreement between political parties and that is probably the last way I would recommend to nurture consent to an agreement from among the public."

All five of the parties represented at the Scottish Parliament - the SNP, Labour, Conservatives, Liberal Democrats and the Greens - have already put forward their submissions to the Smith Commission. Lord Smith said he wants the process to "succeed for the people of Scotland".

He revealed 4,000 members of the public had also been in contact to have their say.