The UK’s trade union movement chief has told Theresa May to “stop playing to the bad boys at the back of the class” over Brexit and “start listening”.
Frances O’Grady said she did not get the guarantees on workers’ rights she wanted in a meeting with the prime minister in Downing Street.
The TUC leader urged Mrs May to take a no-deal Brexit “off the table”.
Mrs May is trying to find compromise with union leaders after her Brexit deal was voted down by MPs last week.
But some of them have backed delaying Brexit and others support another poll.
It comes a day after Sony announced it was planning to move its European headquarters from the UK to the Netherlands to avoid disruptions caused by Brexit.
And Aeroplane maker Airbus has warned that it could move wing-building out of the UK in the future if there is a no-deal Brexit.
The UK is due to leave the EU at 23:00 GMT on 29 March.
After her meeting the prime minister, Ms O’Grady said workers were worried about their jobs and needed reassurances about their future.
“We have a prime minister on a temporary contract – she cannot bind the hands of a future prime minister,” the TUC general secretary said.
“People wanting her job are on record as saying Brexit is an opportunity to reduce workers’ rights.
“The prime minister, frankly, has to stop playing to the bad boys at the back of the class and start listening to where I think Parliament is, which is wanting no deal off the table and more time for genuine talks to take place.
“But get on to priorities that matter to working people in Britain.”
Unison leader Dave Prentis said he believed it to be “in everyone’s interest” that Article 50, the process taking the UK out of the EU at the end of March, was extended.
“Time is precious and we do need that time,” he said.
“We would want Theresa May to move away from just appeasing the right wing of the Tory party and to actually talk about what is best for this country.”
He also called for no deal to be ruled out and for a move towards remaining in a customs union.
Mrs May is also due to meet leaders from Unite and the GMB.
Mrs May spoke to a number of union leaders ahead of the vote on her deal last Tuesday, hoping to drum up support – but it did not pay off, with MPs rejecting her proposals by 230 votes.
Since the defeat, she has been meeting leaders of opposition parties and factions within her own as she called for MPs to “work constructively together” to find a way forward.
Labour leader Jeremy Corbyn has refused to join the talks until Mrs May rules out the UK leaving the EU with no deal, which he says would bring “chaos” to the country.
However, the head of Unite Len McCluskey, who is a close ally of Mr Corbyn, will be among the union leaders she meets later.
What options for Brexit do the unions back?
The TUC’s Frances O’Grady, Unison leader Dave Prentis and the general secretary of the GMB, Tim Roache, have all publicly backed extending Article 50 – the mechanism by which the UK leaves the EU – to postpone the exit date of 29 March.
All three have also said the government should give the public the final say, either through a referendum or general election.
But Mr McCluskey is against another referendum on the EU, writing in the New Statesman that it “risks tearing our society apart”.
On Wednesday, the PM met the first ministers of both Scotland and Wales on the future of her Brexit deal, but both said she seemed unwilling to compromise.
Scottish First Minister Nicola Sturgeon said there “wasn’t much indication that the prime minister is listening to, or hearing the concerns of people in Scotland”, while Welsh First Minister Mark Drakeford said she “repeated many of her red lines”.
How are MPs trying to move Brexit plans on?
The PM is hoping to tweak her deal to address concerns about the Northern Irish “backstop” among her own backbenchers and Northern Ireland’s Democratic Unionist Party, which she relies on to keep her in power, ahead of another vote on her proposed way forward next Tuesday.
The backstop is the “insurance policy” in the withdrawal deal, intended to ensure that whatever else happens, there will be no return to a visible border between Northern Ireland and the Irish Republic after the UK leaves the EU.
Both the UK and the EU believe that bringing back border checks could put the peace process at risk but critics say the backstop keeps Northern Ireland too closely aligned with the EU and separate from the rest of the UK – and that the UK would be permanently trapped in it.
However, a number of MPs are proposing amendments putting forward alternative plans to the PM’s deal with the EU – including seeking an extension to the UK’s exit date.
Labour MP Yvette Cooper has tabled one that would give time for a bill to suspend the Article 50 process for leaving the EU – enabling it to last until the end of the year – if a new deal has not been agreed with Brussels by the end of February.
Her Labour colleague, Rachel Reeves, has also tabled an amendment to extend Article 50.
BBC political correspondent Iain Watson said the pair met Mr Corbyn to discuss the proposals.
He said they recognised that, as Ms Cooper’s amendment would lead to a bill, it would be amendable – meaning the nine-month extension could be significantly reduced to reassure MPs nervous of the timeframe.
Ms Cooper’s amendment is also backed by several Remainer Conservatives and is the only amendment that would be legally binding on the government, if passed.
Conservative ex-cabinet minister Sir Oliver Letwin, who is supporting moves to delay Brexit, told BBC Radio 4’s Today programme that there was “an open question” over whether the EU would agree to an extension of Article 50, but there had been “strong signals” that they would do so.
He said it was “possible but unlikely” that the EU would say: “We’re not going to give you any more time to do that, you can just jump out of the plane without a parachute and leave without a deal.”
Other amendments would ask the government to consider a range of options over six full days in Parliament before the March deadline, to set up a “Citizens’ Assembly” to give the public more say or to insist on “an expiry date to the backstop”.
What’s the view from the EU?
The EU’s chief Brexit negotiator Michel Barnier, who is in Berlin for talks with Chancellor Angela Merkel, reiterated on Germany’s Deutschlandfunk radio that there can be no time-limit on the proposed backstop.
He said that Brexit would be “bumpy” if the UK’s Parliament failed to come together to support a deal.
“If nothing moves, if no positive suggestions are put on the table, then we will be heading for a more or less bumpy or accidental no-deal on 30 March,” he said.
Mr Barnier also played down suggestions that the two-year Article 50 process ought to be extended, saying: “I personally believe that we do not need so much more time, but that we now need to make decisions, to be taken by the British government and the Parliament of Great Britain.”