Brian Wilson said he shared people’s “confusion” about the Scottish Labour leader’s proposals for a People’s Constitutional Convention on federalism.
According to The Herald, the former MP predicted that the idea - the centrepiece of Scottish Labour’s conference in Perth, which finished yesterday - would not work because there was a lack of appetite for the move towards a combination of a UK-wide central government and strong regional governments in England.
Labour brought forward a plan for regional devolution in 2004 under then deputy prime minister John Prescott.
However, voters rejected a northeast of England regional assembly by four to one.
Mr Wilson said that, without such regional devolution, a federal UK would be dominated by England, because of the lopsided, or “asymmetrical”, balance of power.
Labour delegates endorsed Ms Dugdale’s plan on Friday.
Addressing a Fabian Society fringe event, Mr Wilson - a former trade and Foreign Office minister under Tony Blair - was asked how the convention would work in practice.
He said: “I’m not responsible for it. It sounds to me a pretty ropey idea, I have to say.
“I don’t have a problem with federalism, but the basic problem is that England doesn’t want federalism. This was John Prescott’s solution. The problem is the asymmetry of it.
“The only way you get symmetry is if the English regions had any interest in it, and they don’t.
“Well, they didn’t. I doubt if they do now. You’d spend a hell of a lot of time and effort finding out and probably get the same answer.
“I’m not sure what another constitutional convention would do except create another platform for the demands with which we’re all familiar.”