LONDON－Britain on Thursday gained a clear path toward the exit gate from the European Union in just three weeks.

Prime Minister Boris Johnson's fast-track bid to "get Brexit done" cleared its most significant hurdle when his European Union Withdrawal Bill was approved by the House of Commons with a vote of 330 to 231.

The bill will be debated in the House of Lords next week, but given its clear run in the Commons, it is not expected to face any tough opposition. It is almost certain to win royal assent from Queen Elizabeth within days of the Lords vote.

Brexit Secretary Stephen Barclay said he had no doubt politicians in the Lords "will have heard the resounding message from the British people on Dec 12 (the general election day)" and will have seen the clear will of the House of Commons.

Not joining in the celebrations was Ian Blackford, the Scottish National Party's leader at Westminster, who warned Brexit would cause a constitutional crisis for the United Kingdom.

"Today will go down as the final nail in the coffin for this broken union－as Scotland faces being dragged out of the EU against our will by an extreme Tory government with no mandate here," he told MPs after the voting concluded on Thursday.

Blackford said Scotland would at some point have an independence referendum and would remain as an independent European country.

Johnson on Wednesday ruled out a Scottish referendum, saying the people of Scotland voted in a "once in a generation" poll in 2014 to remain part of the UK.

Despite Johnson's repeated promise to get Brexit done on Jan 31, the departure will mark only the start of the first stage of the country's exit from the EU. Britain and the EU will then launch into negotiations on their future relationship, racing to strike new relationships for trade, security and a host of other areas by the end of 2020.

"Leaving the EU doesn't mean that we will have got Brexit done," said Paul Blomfield, a Brexit spokesman for the main opposition Labour Party. "We'll have completed the first step, departure, but the difficult stage is yet to come."

Tough job ahead

Top EU officials are already saying that sealing a new deal will be tough.

Michel Barnier, the EU's chief Brexit negotiator, said on Thursday that Britain's goal of striking a full free-trade agreement by the end-of-year deadline that Johnson insists on is unrealistic.

"We cannot expect to agree on every aspect of this new partnership," Barnier said, adding: "We are ready to do our best in the 11 months."

International trade agreements typically take years to complete, but Johnson has ruled out extending a post-Brexit transition period agreed by the two sides beyond the end of 2020. The EU has offered to prolong it until 2022.

That has set off alarm bells among UK businesses, which fear Britain could face a "no deal" Brexit at the start of 2021. Economists say that would disrupt trade with the EU－Britain's biggest trading partner－and plunge the UK into recession.

Britain and the EU will have to strike deals on everything from trade in goods and services to fishing, aviation, medicines and security.

The EU insists there is no way to deal with all these issues in less than a year. British officials have suggested they could carve the negotiations up into chunks, sealing deals one sector at a time.