Is a federal UK how best to keep it together?

Philip Johnston writes in The Telegraph:

The all-party Constitutional Reform Group (CRG) has just published proposals for a new Act of Union that would effectively turn the county into a federation, with four self-standing national units voluntarily pooling their sovereignty to a central administration. At its most radical, the plan would see an English Parliament and the replacement of the House of Lords with a new second chamber drawn from the four parts of the UK.

The proposals “start from the position that each of England, Scotland, Wales and Northern Ireland is a unit that both can and should determine its own affairs to the extent that it considers it should; but that each unit should also be free to choose to share, through an efficient and effective United Kingdom, functions which are more effectively exercised on a shared basis”. 

Common UK functions might include the constitutional monarch as head of state, national security, foreign affairs and defence, human rights, immigration, the supreme court, the currency, a central bank, some taxation powers, and the civil service. Everything else would be controlled by the nations and regions

This is a complete reversal of what happens now, where a central government devolves power to the periphery as it sees it fit.

This is the model which I think will best preserve the UK. Four national parliaments and one UK Parliament that has a limited role.