Lord Advocate James Wolffe QC said the Scottish Government was not asking for a veto by intervening in the case, but said MSPs were entitled to a vote before the triggering of Article 50 of the Lisbon Treaty, which starts the two-year process of negotiating the UK’s withdrawal from the EU.
In submissions to 11 justices in the UK’s highest court, Mr Wolffe said whether Scotland consented is “a matter of constitutional significance”. He argued EU law provisions would become redundant following withdrawal from the EU with a whole series of effects on Scotland’s devolved legislative powers.
The Lord Advocate said: “Ultimately the approach I invite the court to take reflects the proper institutional roles of the UK Parliament and the Scottish Parliament, in a context where the Scottish Parliament has wide legislative competence and the effect of withdrawal from EU would be significant with regard to devolved matters.
“In that context it is constitutionally relevant and significant to know whether the Scottish Parliament consents to those effects. It is then for the UK Parliament to decide, in light of the views of the devolved administration, to decide what to do.”
Mr Wolffe argued that giving notice under Article 50 would require an Act of Parliament at Westminster and a legislative consent motion from Holyrood.
And he said that the Sewel Convention, which says the UK government should consult Holyrood when legislating on devolved matters, was “part of the law of the land” because it was referred to in the Scotland Act.
The Lord Advocate will continue submissions today, the last day of the hearing.