There are a number of possible post-devolution tensions. As always, money is likely to be an issue. Total funding for Wales, Scotland and Northern Ireland is determined by the Barnett formula, which was intended to bring about a gradual convergence in per capita funding of public services in the different countries, but has not done so.

The latest figures indicate that Northern Ireland and Scotland receive around 30 per cent per capita more than England, while Wales receives around 15 per cent more. The Scottish parliament and Welsh and Northern Ireland assemblies will be able to determine how much of the total is spent on health, and Scotland will be able to raise a limited amount of additional funding if it decides to use its tax varying powers.

So far the government has indicated that the Barnett formula will continue, but there is likely to be pressure from the English regions to challenge this. Although in overall terms, Scotland and Wales have poorer health status than England, if the healthier home counties are excluded from the statistics there is much less difference in health status between the English regions and Scotland and Wales. A difference of 30 per cent in per capita spending between, for example, the English north-east region and Scotland is hard to justify.

In the longer term, if the Barnett formula becomes unsustainable, what might replace it? Agreeing an alternative mechanism is likely to be as contentious as reforming the electoral system. Even agreeing the process by which a change might be agreed may not be easy.