TOMORROW, I will lead a debate in the House of Lords on a constitutional matter. Thankfully it is not Brexit, although not unconnected.

I will propose setting up a UK Constitutional Commission to look at how the asymmetric devolution that has grown up in the UK might be developed to resolve the various democratic deficits.

This approach can also provide a neat and democratic solution for replacing the House of Lords.

The radical and reforming Labour Government of Tony Blair started the devolution process in 1997. Scotland, Wales and Northern Ireland have their own Parliaments or Assemblies with substantial control over domestic matters, both legislative and administrative.

But, as the Lords Constitution Committee reported in 2016 “the largest and most powerful nation in the UK is without separate recognition and representation”.

There have been various attempts to deal with this, but all have been unsatisfactory. The Tory Government tried a divisive plan based on “English Votes for English Laws” (Evel) with only English MPs able voting on purely English legislation at Westminster. That has been a spectacular failure.

On administrative devolution, there has been an a la carte menu of different schemes with catchy titles like Northern Powerhouse, Metro Mayors, City Deals and Midlands Engine which has produced a piecemeal pattern with most of the power still remaining in Whitehall.

Arguably the most successful have been the eight Metro Mayors, but they have differing degrees of power which leaves them, as the Commons Constitution Committee observed, “struggling with the piecemeal delegation of powers and functions”. Meanwhile, country areas are untouched.

The disparity in fiscal devolution is reflected in the Scottish Parliament controlling 43 per cent of tax revenues, Wales 21 per cent and Northern Ireland 14 per cent while English local authorities collect only nine per cent of their revenue.

So the challenge is how to produce a more coherent and comprehensive system of devolution for the whole UK which also addresses the English democratic deficit.

Some favour an English Parliament which is attractive for legislation but does not deal with the demand for administrative decentralisation within England, where dissatisfaction with Whitehall is just as strong as it was in Scotland.

Various attempts to start regional devolution within England, including John Prescott’s plan which died with a failed referendum in the north-east, have perished because Whitehall departments clung to all the real powers.

The clue to solving the conundrum lies in Scotland where our Constitutional Convention in the1990s produced the blueprint for the Scottish Parliament when Labour came to power in 1997. It involved MPs, peers, political parties, churches, unions and civic society with a high level of public engagement.

Robert Hazell of The Constitution Unit supports a similar UK Constitutional Convention to build cross-party consensus, to develop a more coherent package of reform and generate wide public engagement. The aim would be to produce a coherent and comprehensive structure of devolution for the whole UK.

Such a structure could also enable the House of Lords to be replaced by a Senate of the Nations and Regions indirectly elected by the devolved authorities. Such a chamber would then have some democratic legitimacy without challenging the primacy of the House of Commons.

The Liberal Democrats, as federalists, support a Convention and Labour is committed to setting up one when in power.

I don’t see why, if the present Government refuses to set one up, it cannot be done now by Labour, other parties and bodies, as we did in Scotland, so we again have a blueprint ready to implement. Where Scotland led, the UK can surely follow.