Three years since Britain voted to leave the EU and almost two months after the planned departure date, Prime Minister Theresa May is mounting a last bid to try to get the deeply divided parliament’s backing for a divorce deal and leave office with some kind of legacy.

The odds do not look good. Despite offering what she described as “significant further changes”, many lawmakers, hardened in their positions, have already decided not to vote in June 2019 for the Withdrawal Agreement Bill, legislation which implements the terms of Britain’s departure.

Speaking at the headquarters of PricewaterhouseCoopers, May appealed to lawmakers to get behind her deal, offering, as incentives, the prospect of a possible second referendum on the agreement and closer trading arrangements with the EU.

“I say with conviction to every MP or every party: I have compromised, now I ask you to compromise,” she said.

“We have been given a clear instruction by the people we are supposed to represent, so help me find a way to honour that instruction, move our country and our politics and build the better future that all of us want to see.”

By offering the possibility of holding a second vote on her deal and a compromise on customs arrangements, May hopes to win over opposition Labour lawmakers, whose votes she needs to overcome resistance in her own Conservative Party.

But she has infuriated Brexit-supporting lawmakers, who have described a customs union with the EU as no Brexit at all.

Simon Clarke, a Conservative lawmaker, said on Twitter he had backed her deal during its third failed attempt in parliament, “but this speech from the PM means there is no way I will support the Withdrawal Agreement Bill”.

“So if we pass the Withdrawal Agreement Bill at 2nd reading, we allow a Remain parliament to insist upon a 2nd referendum and a customs union? This is outrageous,” he said.

May’s movement towards what many describe as the “Remain” lawmakers, who want to stay in the EU, is a shift for a prime minister who has long said she is against a second referendum and staying in a customs union with the bloc.

She may be counting on the fact that parliament has yet to vote in favour of a second referendum and that a “temporary” customs union might just be weak enough for some in her party to accept.

But it signals how her earlier strategy, to keep Brexit supporters on board, has failed and the last-ditch attempt to get Labour on board, some lawmakers say, is simply too little, too late.

Earlier, John McDonnell, Labour’s finance policy chief, cast doubt on whether it could win the party’s support, saying what he had seen so far “doesn’t inspire confidence, and I don’t think that many of our members will be inspired by it”.

Brexit-supporting Conservatives were equally unconvinced.

David Jones, a former minister, described the speech as “unacceptable” and predicted that the move just before Thursday’s elections to the European Parliament would only buoy support for veteran eurosceptic Nigel Farage’s Brexit Party.

“I believe more Conservatives will vote against it,” he told Reuters.

“Regrettably, it will probably also boost the Brexit Party vote on Thursday.”

May wants to get her withdrawal deal, agreed with the EU in November 2018, through parliament so she can leave office, as promised, having at least finalised the first part of Britain’s departure and prevented a “no deal” Brexit, an abrupt departure that many businesses fear will create an economic shock.

Finance minister Philip Hammond rammed the point home in parliament on Tuesday when he said a no-deal Brexit would leave Britain poorer. He is expected to send the same message to business leaders in a speech later in the day.

“The 2016 Leave campaign was clear that we would leave with a deal,” he will say, according to advance extracts.

“So to advocate for ‘no deal’ is to hijack the result of the referendum, and in doing so, knowingly to inflict damage on our economy and our living standards. Because all the preparation in the world will not avoid the consequences of no deal.” DM

Additional reporting by Costas Pitas and Kylie Maclellan; Editing by Stephen Addison and Gareth Jones.