LONDON: British Prime Minister Theresa May is facing a second defeat in the House of Lords on whether to give parliament the final say on leaving the EU but her timetable for triggering Brexit by the end of the month remains on track.

The bill empowering May to start the exit process has already been held up by a week after peers voted on March 1 for an amendment guaranteeing the rights of European citizens living in Britain.

Members of the unelected upper chamber are on Tuesday expected to back a second change that would give parliament a vote on the final withdrawal deal and any future trade ties with the European Union.

May is confident the bill will pass in time to meet her deadline of triggering Article 50 of the EU’s Lisbon Treaty, which begins the two-year withdrawal process, by the end of March.

But a second defeat would be blow to the Conservative leader, potentially bind her hands in the forthcoming negotiations, and further delay the bill by setting up a stand-off between the House of Lords and the elected lower House of Commons.

It would also be a further sign of the domestic opposition she could face as she negotiates Brexit, prompting calls from some Conservatives for a snap election to increase her currently slim majority in the Commons.

“The government could face many close votes, concessions or defeats as it tries to implement Brexit,” former party leader William Hague wrote in the Daily Telegraph.

The Conservatives are currently well ahead in opinion polls, but changing the law to bring the election forward from 2020 would not be easy, and for now Downing Street is publicly ruling it out.

May has repeatedly urged the Lords not to amend the two-clause bill, saying it is designed only to implement the June referendum vote for Brexit.

But a source from the opposition Labour Party told AFP it expected to win “handsomely” on the issue of a final vote thanks to cross-party support.

EU leaders have signalled that the upcoming negotiations will not be easy, amid fears that other member states could follow Britain out the door.

‘Bad deal’

May says she is optimistic about the talks but is willing to walk away without any agreement rather than accept a “bad deal”.

Opponents fear this would cause chaos, as all trade deals and contracts between Britain and its 27 former EU partners would become void overnight.

The Lords amendment demands that parliament, not the prime minister, makes the final call.

“Engaging parliament throughout the process can only but help improve the prime minister’s negotiating hand,” said Labour’s Brexit spokeswoman in the Lords, Dianne Hayter.

“A vote at the end will, I am sure, be conducted in the best interests of our country.”

May’s spokesman has warned however that such a move could “incentivise the EU to offer us a bad deal in the hope that it stops us leaving”.

“The prime minister wants an unamended bill,” he said.

Peers voted last week for an amendment demanding ministers protect the rights of more than three million European citizens living in Britain after Brexit.

The change dashed May’s hopes of securing approval for the bill this week, as it must now return to MPs for deliberation, likely on March 13.

Ministers will seek to overturn the change in the Commons, and if successful, the bill would return to the Lords in a process known as parliamentary “ping-pong”.

If the Lords back Tuesday’s amendment, this too must be reviewed by the Commons — where reports suggest May could face a rebellion from up to 20 of her Conservative MPs.

Among them is former minister Anna Soubry, who warned at the weekend: “If we are faced with a potentially catastrophic ‘falling off a cliff’, the least we can do is provide a parliamentary safety net.”

A new poll for the Independent newspaper found that only 25 per cent of people would support leaving the EU without a deal, which business leaders have said would be like opening a Pandora’s box.