The European Union's chief negotiator on Monday shut down hopes of a Brexit compromise with Brussels, saying it was up to Britain's government and parliament to find a way forward with less than three weeks to go before the scheduled departure date.
On the eve of a crucial vote in the House of Commons on Prime Minister Theresa May's divorce deal, Michel Barnier told AFP the British leader must negotiate with MPs rather than the EU.
"We held talks over the weekend and the negotiations now are between the government in London and the parliament in London," Barnier said in Brussels ahead of Brexit discussions with envoys from the other 27 member states.
May will update lawmakers later Monday on what changes, if any, she has secured to her EU divorce deal which was agreed with the bloc last year but overwhelmingly rejected by MPs in January.
Following that crushing defeat she agreed to renegotiate certain unpopular aspects of the agreement and hold another vote this Tuesday.
But as parliament prepares to reassess the deal, the prime minister has little to show for her efforts, prompting warnings of another humiliating loss.
"Discussions are ongoing between ourselves and the EU," May's spokesman told reporters, insisting that Tuesday's vote would take place as planned.
Failure means Britain could end 46 years of ties with its closest trading partner on March 29 with no new arrangements in place, causing huge disruption on both sides of the Channel.
It would also raise the possibility of a delay to Brexit, with further votes on leaving without a deal and postponing Britain's departure date set for later in the week if May's deal falls.
While europhiles in May's Conservative Party would welcome a delay as a possible precursor to a second referendum on EU membership, eurosceptics strongly oppose it.
May and European Commission chief Jean-Claude Juncker spoke by phone on Sunday night and agreed to remain in touch Monday, but no further technical talks between officials were scheduled, according to a European source.
Influential Labour opposition MP Yvette Cooper urged May "to accept that her approach is not working" and that now was the time "to pivot not dig in".
"The clock is truly run down, the can kicked and squashed, the road has run out," she said Monday, warning that MPs were ready to try to wrestle control of the process.
Loyal ministers concede the deal is not perfect but say it is the best way to move forward -- and that rejecting it could put Brexit at risk.
In the face of a revolt within her split cabinet, May has promised that if MPs defeat her plan, they will be able to vote Wednesday on whether to leave the EU with no deal, or the following day on seeking a delay.
But any postponement would have to be approved by the leaders of the other 27 nations, who are next meeting at a Brussels summit on March 21-22 -- a week before Brexit day.
The agreement was struck over more than a year of tough negotiations, and covers Britain's financial settlement, expatriate rights, the Irish border and plans for a transition period.
But MPs on all sides in London were swift to condemn it for a variety of reasons, and it was rejected in January by 432 votes to 202.
MPs then voted to ask May to seek changes to the most controversial element, the backstop arrangement intended to keep the Irish border open after Brexit.
This would keep Britain in the EU's customs union and parts of its single market until and unless another way -- such as a trade deal -- is found to avoid frontier checks.
Many MPs fear it is a "trap" to keep them tied to EU rules, but Brussels has rejected calls for a time limit or unilateral exit clause.