What's more, their plans are endorsed by the TUC and the major local authority associations. Even the Archbishop of Canterbury has a kindly word to say for them.
Fantasy? South of the border, undoubtedly yes. But this would be the English equivalent of what has just happened in Scotland. The proposals for a new devolved Scottish parliament, which were formally endorsed yesterday by the Scottish Constitutional Convention, are indeed a remarkable development.
Even viewed with Scottish eyes, yesterday's agreement was significant. The political parties, the key players, started poles apart. The Liberal Democrats favoured a federal structure for the whole of the UK, with England and Wales, as well as Scotland, having their own parliaments. Labour, in contrast, was committed to a Scottish parliament that would have significantly more powers than anything that might be created south of the border. The Liberal Democrats still retained their faith in the single transferable vote system of proportional representation. Labour preferred first-past-the-post.
Yet despite these differences both parties are jointly committed to a detailed agreement to change radically the way Scotland is governed.
While it may be remarkable, does it matter? Why has Labour, which dominates Scottish politics, felt it worthwhile to talk to the Liberal Democrats, who have the support of little more than one in ten Scots?
A look at the history of constitutional change in post-war Britain provides the answer. It is littered with failure. Harold Wilson attempted to reform the House of Lords in the Sixties, and was defeated by an unholy alliance between Michael Foot and Enoch Powell. And in the Seventies devolution for Scotland itself was lost thanks to the Labour MP George Cunningham's backbench amendment requiring that the proposals be endorsed by the support of 40 per cent of all Scots in a referendum.
Thus on both occasions governments were defeated by their own backbenchers. As John Major discovered with the Maastricht Bill, proposals for constitutional change are particularly vulnerable to backbench rebellions because all MPs take part in the detailed committee stage of the Bill rather than just a small group hand-picked by the whips.
Labour cannot be sure that its proposals for a Scottish parliament would not cause divisions in its ranks once again. Labour MPs from the north of England may well have some worries that creating a Scottish parliament in the absence of any clear commitment to regional assemblies for England could be to the disadvantage of their constituents. They might be particularly concerned, for instance, about the parliament's ability to direct industrial policy and regeneration programmes.
But north of the border, Labour needs to demonstrate that, unlike in the Seventies, this time it can deliver. Whereas in England, Labour's electoral task may be to overturn the Tories, in Scotland its job is to keep at bay a nationalist party which in the past three years has clearly established itself as the principal opposition.
This is where yesterday's agreement is vital. By agreeing with the Liberal Democrats much of the detail about how a Scottish parliament should be formed, Labour's claim that this time it will succeed where previously it failed looks far stronger.
But the critics of devolution will still find plenty of ammunition to fire at this document. The most difficult job in establishing any devolved parliament is getting its relationship with Westminster right. And on at least three counts these proposals may not achieve that task. First, the Convention admits that what Westminster gives, ultimately it can take away. It has not found a way of entrenching a Scottish parliament so that it cannot be abolished by a future House of Commons.
Instead, it claims that no Westminster government would dare to abolish a parliament that clearly had the support of the people. Yet no provision is made to demonstrate the existence of that support by holding a referendum before the parliament is established.
Second, the parliament will still be primarily reliant on Whitehall for its funds. The Convention has drawn back from the idea of assigning to Scotland the taxes raised in Scotland, presumably because it has found that they are insufficient to fund what is spent in Scotland now.
Instead the parliament will receive the funds that now go to the Scottish Office. True, these are currently fixed by formula, but it still means that if expenditure is cut in England, Scotland's budget is reduced, too. A Labour parliament in Edinburgh could still find itself at the mercy of Conservative cuts at Westminster.
Of course, the new parliament is to have its own tax-raising power, by raising (or cutting) income tax by up to three pence in the pound. But income tax is the most politically sensitive of all taxes, a fact that the Scottish Secretary, Michael Forsyth, has already exploited effectively by dubbing the proposal a "tartan tax". In short, the only weapon the parliament will have in its battle with Westminster is a nuclear one that could well blow up in its backyard, rather than in London.
Third, the proposals are decidedly vague about the division of legislative powers and responsibilities between Westminster and Edinburgh. In particular there are no firm proposals about how disputes between the two bodies might be resolved.
The Convention's proposals, then, are an important step on the road to making a devolved Scottish parliament a reality. But equally, yesterday's blueprint is very unlikely ever to come to fruition simply in its current form.
The writer is senior lecturer in politics at Strathclyde University and deputy director of the ESRC Centre for Research into Elections and Social trends.