A ‘reserved powers’ approach to devolution in Wales would offer a number of significant advantages, but applying such a model will not be straightforward. Drawing on research conducted with the Wales Governance Centre and the Constitution Unit for a report published this week, Alan Trench outlines the key challenges.
The debate about a ‘reserved powers’ model for the National Assembly has to be one of the most obscure legal issues to enter public debate. The basic idea is straightforward: that the powers of the National Assembly should be defined by setting out what it cannot do, rather than by defining ‘subject areas’ where it does have power to pass laws. The idea is scarcely novel – it was mooted by the Richard Commission in 2004, and repeated by the Silk Commission in 2014 – but it has acquired political legs following the St David’s Day process with all the parties agreeing to adopt it.
A ‘reserved powers’ approach would offer a number of significant advantages. It would mean that Welsh devolution works in a similar way to that in Scotland and Northern Ireland – important both symbolically and as a way of making it clearer to the public how a devolved UK works. It also offers a way to resolve the puzzle created by the UK Supreme Court’s jurisprudence about devolution, and particularly its judgment in the reference about the NHS Recovery Of Medical Costs for Asbestos Diseases (Wales) Bill,  UKSC 3, by enabling the Assembly to legislate for all matters save expressly those reserved to Westminster. In broad terms, the Scotland Act 1998 provides a valuable model – not necessarily so much in the list of reserved matters in Schedule 5 as in the provisions of the Act for identifying the scope of those reservations and interpreting them in the courts. At present, the list of proposed reserved matters suggests a list of matters Whitehall departments do not wish to see devolved, unsupported by any wider rationale or principle. That is not the right way to proceed when drafting a constitution. It needs some clearer and stronger basis, rooted in a conception of what the UK needs to do at the centre (and why), and what is best done by devolved governments.