British lawmakers on Thursday passed a bill approving the U.K.’s departure from the European Union at the end of the month, signaling a possible end to three and a half tumultuous years of Brexit negotiations.

Lawmakers voted by 330-231 to pass the Withdrawal Agreement Bill, which sets the terms of Britain's departure from the 28-nation bloc. The comfortable majority won by Prime Minister Boris Johnson's Conservatives in last month’s election secured the bill's passage despite the opposition of minority parties.

Britain's Prime Minister Boris Johnson gestures during the first Prime Minister's Questions of the year, in the House of Commons in London. (House of Commons via AP)

After passing through Parliament's House of Lords, the bill should become law in time for the U.K. to leave the EU on the scheduled date of Jan. 31 and become the first nation ever to quit the bloc.

Thursday's vote was a major victory for Johnson, who has made delivering Brexit the key aim of his premiership. Before the Dec. 12 election, lawmakers had repeatedly defeated attempts by both Johnson and his predecessor Theresa May to secure backing for their Brexit plans.

The Jan. 31 departure will only mark the start of the first stage of the country's EU exit. Britain and the EU will then launch into negotiations over 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 Labour Party. "We'll have completed the first step, departure, but the difficult stage is yet to come."

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Top officials in the bloc are already saying that sealing a new deal will be tough given that international trade agreements typically take years to complete. 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.

Both sides also have conflicting demands that are likely to complicate negotiations. Johnson says the U.K. wants a wide-ranging free trade deal with the bloc without the EU’s rules and standards. The EU says the U.K. won't get good access to its market unless it agrees to alignment.

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As a member state, Britain was bound by strict state aid rules enforced by the powerful European Commission to make sure there is no unfair competition among nations inside the EU's vast single market. Third countries aren't immediately bound by such strictures.

The Associated Press contributed to this report.