10:51

Nicola Sturgeon’s bid to hold a vote at Holyrood on giving legislative consent to the UK government’s bill to trigger article 50 could be blocked by the parliament’s presiding officer, Ken Macintosh, if he decides it is outside Holyrood’s competence.

Sturgeon has said she wants to table a legislative consent motion (LCM) at Holyrood to allow the parliament to symbolically reject the UK government’s article 50 bill, because Brexit will directly affect Holyrood’s powers.

However, that power appears to be in doubt after Lord Neuberger, the president of the supreme court, said all 11 judges had “unanimously rule[d] that UK ministers are not legally compelled to consult the devolved legislatures before triggering article 50”.

The court ruled that EU and international treaties were clearly outside the scope of the Sewel convention, which states the UK’s devolved parliaments have to pass a LCM on UK legislation which affects their powers or remit.

In a possible lifeline to Sturgeon, the judges added, however, that the exact scope and enforcement of the convention was not a matter for the courts, since it was a political convention and had no legal force.

Holyrood’s standing orders allow MSPs to debate LCMs on issues that alter Scotland’s legislative competence. But the last presiding officer, Tricia Marwick, has rejected a previous attempt by Scottish ministers to use an LCM to object to controversial UK legislation on restricting trade union rights in December 2015.

A Holyrood spokeswoman said: “The presiding officer cannot reach a decision on whether the LCM process can proceed until a bill is introduced to the UK parliament and a draft legislative consent memorandum has been submitted to the Scottish parliament. We will not prejudice this decision by speculating in advance.”