Theresa May has been granted the power to formally start the Brexit process whenever she wants, after parliament approved legislation on Monday night granting the government the power to invoke Article 50. However, it's still not known when she will use it.
The prime minister can now legally declare the UK is beginning the two-year process to leave the European Union as soon as the Queen signs the bill into law – which could happen as soon as tomorrow.
It had been widely expected she would announce the process was beginning on Tuesday, but her spokesperson has now suggested the announcement will be made at "the end of March".
Last week a cross-party alliance of peers succeeded in amending the legislation to require parliament to be given a meaningful vote on the UK's post-Brexit trade deal as well as enshrining the rights of EU citizens already living in the UK.
Theresa May ordered her party to overturn these amendments in the House of Commons on Monday night, easily defeating opposition from Labour and Liberal Democrat MPs.
The legislation then went back to the House of Lords, where Labour abstained in order to avoid being seen as attempting to overrule the will of democratically elected MPs.
Labour's Lady Hayter said the party accepted parliament's verdict and would instead look forward to trying to influence the next two years' of Brexit negotiations.
"We have heard, regrettably, that the Commons has not heard the vote in this house," she said.
"We will need to negotiate with the EU in a way that shows our openness and our willingness to retain our strong bonds, because that will influence our relationship with the EU as a bloc. It is for this reason that it is important to recognise parliament's role in the process."
The Labour politician also criticised the Liberal Democrats' "pointless gesture" of attempting to overturn the verdict of the House of Commons in the House of Lords.
Conservative Brexit minister Lord Bridges defended the decision to give full authority over the terms of leaving the EU to the prime minister, saying: "It is the culmination of a long democratic process, a process started by the people at the last election, endorsed by this house in an act of parliament, and then voted for by the people at the referendum itself."
He added: "This bill is to trigger the process of our leaving and fulfil the Supreme Court's requirements. Tonight we might just make it to the legislative base camp in terms of parliament scrutiny and debate. There is a lot, lot more to come."
The government's plans have also been disrupted by Scottish first minister Nicola Sturgeon's decision to call for a second referendum on Scottish independence while negotiations are underway.
Secretary of state for exiting the EU David Davis said: “Parliament has today backed the government in its determination to get on with the job of leaving the EU and negotiating a positive new partnership with its remaining member states.
“We are now on the threshold of the most important negotiation for our country in a generation.
“We have a plan to build a global Britain, and take advantage of its new place in the world by forging new trading links.
“So we will trigger Article 50 by the end of this month as planned and deliver an outcome that works in the interests of the whole of the UK.”
Labour leader Jeremy Corbyn insisted his party would "at every stage” challenge a deal that resulted in a "bargain basement Brexit".