Britain has lurched closer to leaving the European Union, with Parliament giving Prime Minister Theresa May the power to file for divorce from the bloc.

But in a blow to Ms May’s Government, the prospect of Scotland’s exit from the United Kingdom suddenly appeared nearer, too.

Scottish First Minister Nicola Sturgeon called for a referendum on independence within two years to stop Scotland being dragged out of the EU against its will.

Ms Sturgeon spoke in Edinburgh hours before the EU (Notification of Withdrawal) Bill passed its final hurdle in Parliament’s upper chamber — the House of Lords.

The House of Commons approved the bill weeks ago, but the 800-strong Lords fought to amend it, inserting a promise that EU citizens living in the UK would be allowed to remain after Britain pulls out of the bloc.

They also added a demand that Parliament get a “meaningful” vote on the final deal between Britain and the remaining 27 EU nations.

Both amendments were rejected on Monday by the Commons, where Ms May’s Conservatives have a majority.

A handful of pro-EU Conservatives expressed their unhappiness, then abstained from the vote.

The bill returned to the Lords, in a process known as parliamentary ping-pong. Faced with the decision of the elected Commons, the Lords backed down and approved it without amendments.

Labour peer Dianne Hayter, who proposed the amendment on EU citizens, said the Lords had done their best, but “our view has been rejected in the elected House of Commons, and it is clear the Government is not for turning”.

Once the bill receives royal assent — a formality that should be accomplished within hours — Ms May will be free to invoke Article 50 of the EU’s key treaty, triggering two years of exit negotiations, by her self-imposed deadline of March 31.

Ms May was forced to seek Parliament’s approval for the move after a Supreme Court ruling in January torpedoed her attempt to start the process of leaving the bloc without a parliamentary vote.

Millions of residents in limbo

The House of Commons and House of Lords battled over the bill’s contents, with the status of EU nationals in Britain — and Britons in fellow EU member countries — drawing especially emotional debate.

Both British and EU officials have said such residents should be guaranteed the right to stay where they are, but the two sides have so far failed to provide a concrete guarantee, leaving millions of people in limbo.

Brexit Secretary David Davis told politicians the Government had a “moral responsibility” to the 3 million EU citizens living in Britain and the 1 million Britons in other member states, and intended to guarantee their rights as soon as possible after exit talks start.

Pro-EU politicians accused the Government and those backing Brexit of running roughshod over the concerns of the 48 per cent of Britons who voted to stay in the EU.

Conservative legislator Dominic Grieve called the Government’s opposition of handing Parliament a final vote on Brexit “deranged”, and the Green Party’s Caroline Lucas said politicians should not just hand ministers a blank check.

“We were not elected to be lemmings,” Ms Lucas said.

Ms May is now free to trigger Article 50 as early as Tuesday, but the Government signalled the move would come much closer to the March 31 deadline.

Ms May’s spokesman James Slack repeated the Government’s position it would happen by the end of March.