What are reserved powers?

Reserved powers are the areas of decision-making that stay with the UK Parliament at Westminster. They are not devolved to Scotland, Wales or Northern Ireland. They include defence, foreign affairs, immigration, the constitution, currency and most economic policy. Anything not listed as reserved is generally devolved.

Scotland has used a reserved powers model since 1999. The Scotland Act 1998 lists the reserved matters, and everything else is devolved. Wales moved to the same model in 2018 under the Wales Act 2017. This made the boundaries clearer than the old system, where Wales could only act in listed areas. Northern Ireland's model differs slightly from the other two.

Reserved matters include the Union itself, defence, foreign policy, immigration and nationality, the currency, financial services, most energy policy, broadcasting, and employment law. Most social security was reserved, though Scotland now runs some disability and carer benefits. Northern Ireland has a similar split between excepted matters, which never move, and reserved matters, which can be transferred later. Some areas are shared.

Disputes over what is reserved can end up in court. In 2022 the UK Supreme Court ruled that holding an independence referendum relates to the reserved matter of the Union. So the Scottish Parliament could not legislate for one without Westminster's agreement. Westminster can also legislate on devolved matters, though by convention it does not normally do so without consent. The UK Internal Market Act 2020 sparked fresh rows.