Brexit Bill faces final Parliamentary hurdle as Article 50 trigger looms

Theresa May could trigger the formal process of Britain's divorce from the European Union within the next 48 hours as a landmark law giving the prime minister the power to start Brexit faces its final Parliamentary hurdle.

MPs are likely to overturn changes to the Brexit Bill made by peers when it returns to the Commons on Monday afternoon following two defeats in the Lords.

Backing by the Lords when the legislation is sent to the upper chamber in the evening would allow the Prime Minister to fire the starting gun on exit talks as early as Tuesday.

The House of Lords changed the European Union (Notification of Withdrawal) Bill to introduce a "meaningful" parliamentary vote on the final deal with Brussels and guarantees on protections for EU nationals living in Britain.

Brexit Secretary David Davis called on Parliament to give Mrs May a clear run at the two-year negotiation process that will begin when Article 50 is triggered.

Theresa May sits behind the speaker (far right) in the House of Lords during a debate on the Brexit Bill. Credit: PA

Up to 10 Tory MPs are reportedly considering opposing the government or abstaining in the vote but a rebellion would need to reach higher numbers to derail the process.

Labour sources warned there was a 20% chance of peers sending the Bill back to the Commons again if their amendments are dismissed out of hand, in another round of so-called Parliamentary ping-pong.

Mrs May will go before MPs on Tuesday to update them on talks she had with other EU leaders at a European Council meeting last week.

Speculation is mounting she will use the opportunity to formally announce she is starting the exit process.

The prime minister announced in October that Article 50 would be triggered by the end of March.