Constitution Legal experts differ over power to block Brexit

When the Scottish Parliament was set up, a statement was made by Lord Sewel, who was responsible for the Scotland Act, that the UK Government would not seek to legislate on devolved matters without first receiving the consent of Holyrood.

The convention of this “legislative consent motion” is enshrined in a Memorandum of Understanding and Supplementary Agreements, which outlines the principles of cooperation underpinning the relationship between the UK Government and the devolved administrations.

It says the UK Parliament “will not normally legislate with regard to devolved matters except with the agreement of the devolved legislature”.

Earlier this year, Prof Sir David Edward, a former judge of the European Court of Justice, told the House of Lords select committee on the European Union that he believed the Scottish Parliament would have to give its consent

to measures extinguishing the application of EU law in Scotland, as part of the process of withdrawing from the EU. The committee’s report said he could “envisage certain political advantages being drawn from not giving consent”.

But other legal experts disagree, and point to the fact that the legislation only says the UK Parliament will not “normally” legislate on devolved issues without agreement.

Prof James Chalmers of Glasgow University said consent should be sought from Holyrood but Westminster “has never been required to do that and has always had the power to overrule”. He added: “It wasn’t ever a rule of law, it was just a matter of politeness as much as anything else. It would be politically awkward to do this without legislation consent, but I think the whole thing is so politically awkward that this does look fairly trivial, given all the other problems.”