The Scottish National Party is making a last-ditch bid to block the bill taking the UK out of the European Union from becoming law, on the final day of its passage through parliament.

SNP leader in Westminster Ian Blackford has demanded the right to attend a meeting of the Privy Council to argue the case to the Queen, or a representative of the palace, that Boris Johnson’s Withdrawal Agreement Act should not be given Royal Assent without the consent of devolved legislatures in Scotland, Wales and Northern Ireland.

Royal Assent is the final step which the bill must complete to pass into law, paving the way for the UK to depart the EU on 31 January.

After a historic parliamentary battle which saw Theresa May’s withdrawal plans rejected three times over the course of 2019, eventually leading to her resignation as PM last July, legislation to pass Mr Johnson’s similar plan has enjoyed a much smoother passage onto the statute book.

MPs thwarted his attempt to force it through in time for the scheduled Brexit date of 31 October last year by rejecting his truncated timetable for scrutiny.

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But after he secured a landslide 80-seat majority for Conservatives in December’s general election, a revised bill was tabled within a week and has passed through both houses with a total of 11 days’ scrutiny.

Mr Johnson is expected to be able to use his domination of the Commons to strike out four House of Lords amendments, including on the protection of unaccompanied child refugees and the status of EU expats, with minimal resistance on Wednesday.

This will leave only Royal Assent and ratification in the European Parliament to be completed before Brexit day.

Now Mr Blackford is attempting to disrupt the final steps in the process by writing to Commons Leader Jacob Rees-Mogg to warn him that granting assent without the legislative consent of the Scottish Parliament, Welsh Sennedd and Northern Ireland Assembly would represent a “serious breach” of the so-called Sewel Convention, which underpins the devolution settlement.

"By dragging Scotland, Wales and Northern Ireland out of the EU against the expressed wishes of the Scottish Parliament, Sennedd, and the Northern Ireland Assembly, the Tory government is breaching the devolution settlement and trampling over democracy,” said Mr Blackford.

"Scotland has voted against Brexit at every opportunity - yet the UK government is determined to ignore our views, terminate our EU membership, and deny us any choice over our future.

"The SNP won a landslide victory at the general election - winning 80 per cent of seats in Scotland on a cast-iron mandate to hold an independence referendum. The people of Scotland must have a choice over our future - so we can remain at the heart of Europe as an equal and independent country."

Ian Blackford (BBC)

In his letter, Mr Blackford told Mr Rees-Mogg that a majority of MPs representing Scottish seats supported an unsuccessful amendment to the Queen’s Speech arguing that Royal Assent should not be given without the consent of the three devolved legislatures.

“As a member of Her Majesty’s Privy Council, I am formally requesting the right to attend any meeting of the Council convened for the purpose of granting Royal Assent to the bill,” he wrote.