The problem is how you can have Scottish MPs voting in Westminster on matters that affect England, when Scotland has its own parliament to deal with the same matters; yet if they are forced to abstain, you could have a government some of whose supporters are excluded from legislating on the manifesto it was elected on.
Why not take a leaf out of Europe’s book? If Europe is a community of sovereign nations who have pooled certain powers by agreement through treaties, why should we (in the British Isles) not do the same?
1. Dissolve the UK parliament (so doing away with the House of Lords)
2. Let each constituent country – England, Scotland, Wales, Northern Ireland (or even a united Ireland – who knows? they might want to join) together with crown dependencies such as the Isle of Man and the Channel Islands – have a wholly sovereign parliament with tax-raising powers, elected by those who live there, which orders all the affairs of its territory, subject to the exceptions noted below.
3. Let each constituent parliament delegate a person or persons to attend a council which will agree matters of common interest to this commonwealth of nations; if need be, they can be allocated in proportion to the constituent members. This council will decide such matters as defence, foreign policy and fiscal policy (to the extent deemed necessary for a shared currency). The matters that are remitted to the Council will be for the constituent members to decide. The decisions of the Council must be ratified by the various parliaments, but (as a rule) they will not demur.
4. The constituent countries will make a pledge of mutual succour and support.
5. There will be treaties between the member states on common matters, much as there are in Europe. Borders will be open, trade free, and so on. If thought necessary there will common agricultural and fisheries policies and subsidies on the European model, in line with point 4.
Problem solved. Over to you, Mr Cameron.