Liberal Democrat MEP Andrew Duff, who represents Eastern England, was giving evidence to the European and External Affairs Committee.

“Several clauses in the protocol on subsidiarity could be deployed towards that end,” he told MSPs, but added, “I have no idea how far the case would travel through the court or whether it would be successful”.

However, the new European treaty states that “it will be for each national Parliament or each chamber of a national Parliament to consult, where appropriate, regional parliaments with legislative powers”.

This means that in the case of a complaint, complaints to the European Court of Justice could only be made by member states and therefore any complaint
brought by the Scottish Parliament would have to go through Westminster. Nonetheless, Duff said that if MSPs identified particular issues to Westminster as of being of major importance to Scotland, but were not consulted in a timely manner on these issues, they would be likely to get a sympathetic hearing if they were able to make a complaint.

Duff also told the committee that the relationship between Westminster and Holyrood needed to be defined more clearly. The new treaty does incorporate a greater role for regional parliaments, including greater and earlier consultation on proposed legislation and directives. However, the relationship between national and devolved parliaments remains the business of that nation.