Lying behind IPPR's Devo More programme is the idea that more devolution is not just compatible with strengthening the Union, but vital to doing so for the 21st century.

A stronger form of devolution is clearly the "settled will" of Scottish voters, and increasingly so in Wales too.

In England, there is growing discontent about what is seen as preferential treatment of devolved parts of the UK, and the unfairness involved in the way it is funded. Finding a way of reconciling these different concerns is key to making the Union fit for purpose in a changing world.

What might enhanced devolution look like? First, devolved governments need extensive (though by no means complete) fiscal devolution, accompanied by a grant clearly designed to distribute resources in an equitable way.

That will mean devolved governments can provide a similar quality of services - a fundamental guarantee of fairness across the UK. A package comprising personal income tax, land taxes, and an assigned portion of VAT would both enhance devolved autonomy and help devolved governments to manage the risks associated with fiscal devolution. Income tax is the first, vital step toward achieving that.

None of this would stop the UK Government having substantial tax bases to fund redistribution across the UK if it wished.

Second, social security needs to change. It would be hard if not impossible to devolve the big redistributive benefits like old age pensions and jobseekers allowance. But there is a strong case for devolving those benefits which overlap with devolved functions. Housing benefit is an obvious candidate here.

Third, there needs to be greater awareness of the role of the UK government as a government for England itself. England is not simply a residuum of the UK but one of its component nations, and the English public increasingly wants to see this recognised.

Decentralisation along the lines of city-regions and city deals - a process that is already under way, with broad political support - could be one aspect of this. But it is also important to ensure MPs from English constituencies are given a more explicit role in approving legislation that affects England only - something Scottish as well as English voters support when they are asked.

Ultimately, Devo More would see the evolution of the UK into a rather asymmetric, quasi-federal system, in which emphasis could be put on both devolved autonomy and the value of the Union. Such a scheme is workable in practical terms, and indeed much of it could be put in place relatively quickly, building on existing arrangements or ones currently in train (like tax devolution under the Scotland Act 2012).

It also brings the UK's overall system of government closer to aspirations for it from voters in Scotland and Wales, without undermining the interests of people in England. This means the package is not merely potentially popular, but implementation would contribute to ensuring the ongoing legitimacy of the government across the UK.

Finally, Devo More offers something to each of the major British political traditions and the parties that currently embody them. For social democrats, enhanced devolution reconciles devolved self-government with a framework to assure UK-wide fairness through a system of financial redistribution.

For conservatives, the key element is to combine autonomy with devolved fiscal responsibility - which means transparency about spending decisions, so that voters wanting more spent on public services will have to bear the cost as well.

For liberals, Devo More offers guarantees of fairness as well as autonomy, so that devolved parts of the UK can make meaningful policy choices of their own. For all, it still enables the various parts of the UK to act together when there is a joint interest in doing so.

Devo More offers a way forward, and making sure Scottish voters can get what they want: a high level of self-government while remaining part of the United Kingdom. It balances autonomy and union, in a way that offers a lasting settlement.

IPPR's Devo More paper is published today and available in full here

Alan Trench is Professor of Politics at Ulster University