British MPs look set to approve a bill on Wednesday empowering Prime Minister Theresa May to start Brexit negotiations, in a major step towards Britain leaving the European Union.
Seven months after the historic referendum vote to leave the 28-nation bloc, the House of Commons is expected to grant approval for May to trigger Article 50 of the EU's Lisbon Treaty.
The bill would still need to pass through the House of Lords, where there may be more opposition from unelected peers less concerned about defying the public.
But if, as expected, the bill passes its Commons stage late Wednesday, May will be significantly closer to her goal of starting the two-year exit talks by the end of March.
Under pressure from MPs, the government was forced to concede on Tuesday that parliament would have a vote on the final Brexit deal before it is sent to the European Parliament for approval.
The move helped fend off a rebellion by pro-European members of May's Conservative party over the two-clause bill.
But ministers warned that if lawmakers rejected the final deal, the alternative was not to return to negotiations -- but to leave the EU without any agreement at all.
More than two-thirds of MPs campaigned against Brexit in the deeply divisive run-up to the June referendum, but after 52 percent of Britons voted to leave the EU, most have reluctantly accepted that they must uphold the result.
When May introduced her Brexit bill last month, following a Supreme Court ruling that she must seek parliament's approval to start the divorce, the main opposition Labour party promised not to block it.
It has sought to amend the bill but failed to do so in several attempts this week.
Dozens of Labour MPs could rebel in the final vote, due around 8pm (2000 GMT), in a move that would spell trouble for the party's embattled leftist leader Jeremy Corbyn.
Corbyn has imposed a "three-line whip" demanding MPs support the Brexit bill but last week 47 MPs defied him -- and more have threatened to do so on Wednesday.
They are backed by the staunchly pro-European Scottish National Party (SNP) and the smaller Liberal Democrats, but between them do not have the votes to defeat the government.
The SNP-dominated Scottish parliament voted overwhelmingly against the bill passing through Westminster on Tuesday, but May noted that the devolved assembly "does not have a veto".
Once she begins the negotiations, Britain will be on course to become the first country to leave the EU after four decades of membership.
May has said she would prioritise controlling migration in the talks, at the cost of losing membership of Europe's single market of more than 500 million people.
Concerns over losing access to the continental trading zone have sent the pound plunging around 15 percent against the dollar -- and many MPs are also deeply concerned.
The promised final vote on the "final draft agreement" on leaving the EU will give MPs and peers a say on the exit terms as well as any new trade deal agreed with the bloc.
Many MPs are sceptical that both can be agreed within two years, raising the question of what they would be voting on at the end, although May insisted Wednesday "it is possible".
However, Labour MP Chris Leslie warned: "On the nightmare scenario, that we could leave the EU with no deal at all, and face damaging barriers to trade with Europe, it seems parliament could have no say whatsoever."