W ith a senior political source suggesting it could take three years to deliver greater powers for the Scottish Parliament, where is the reassurance the pre-referendum pledge will be honoured promptly?

It is hard to be reassured by the public statements of the three main parties at Westminster. The latest came from Nick Clegg who says "factionalism" within the Labour party could delay greater powers.

The Liberal Democrat leader said that because Labour appear less willing to agree to full devolution of powers over income tax, it is the "slowest train", and cannot be allowed to dictate the pace. Mr Clegg also says "Conservative game-playing" over English Votes for English Laws (EVEL) has been thwarted.

Meanwhile, leading LibDem David Laws has proposed a grand committee to scrutinise draft legislation affecting only England, to help solve the West Lothian problem. This would prevent Tory domination of a first-past-the -post body, he argued. Despite Liberal efforts to play the honest broker, party interests are now in play on all sides as seen by Mr Laws and Mr Clegg calling for any EVEL system to be based on proportional representation (PR).

This is audacious. It is not just the Liberal Democrats, of course, who fear Conservative dominance of any body set up to approve laws which only have effect in England (however few they may be). But, if their poll ratings improve, they would be the main likely beneficiary of PR, so they are hardly speaking from an impartial position.

That is not to say they are not right about adopting a fairer system. If the UK becomes more federalised, we could do worse than following the Scottish Parliament, and Northern Irish and Welsh Assemblies and be set up on a proportionally elected basis.

Mr Clegg also called for the SNP and the Yes campaign to accept the result of the referendum and move on. In comments which will alienate many, he compared those in favour of independence to soldiers lost in the jungle for decades, constantly fighting a battle, left behind by history.

The current agenda has certainly moved on to the issue of how greater powers for Scotland can be delivered to the timetable promised by the Westminster parties. But it is still more audacious of Mr Clegg to dismiss the aims of the Yes campaign at a time when a surge in SNP membership has demoted his party to only the fourth largest in members in the UK.

Among his comments, Mr Laws praised the last Labour Government for putting aside party advantage to deliver constitutional change. Would there were more of this. The problem with the intervention of senior Liberal Democrats, Mr Cameron's EVEL call and Labour's awkward tax plan for Scotland is that party interest is too evident in all of it.

The Westminster parties misunderstood the Yes campaign and were dismissing it as narrow nationalism right up until the vote one reason why the poll was so close. If they now botch the job of delivering the greater powers promised to Scotland in a battle for narrow party advantage it will only compound the error.