Key British Conservative MP Graham Brady has softened his opposition to Theresa May's Brexit withdrawal deal, although also insisted a backstop 'compromise' is still needed.
Mr Brady is the leader of the powerful backbench 1922 committee.
He successfully submitted the amendment calling on the British government to replace the backstop with unspecified 'alternative arrangements'.
His amendment was backed by a majority of MPs.
While the British government has sought concessions, EU leaders have repeatedly ruled out the prospect of substantial renegotiation of the withdrawal agreement.
The EU's chief Brexit negotiator Michel Barnier, however, has said the EU's ready to give the UK further assurances that the Irish backstop 'should only be temporary'.
Mr Brady now says conversations with European diplomats and politicians have given him "cause for optimism that a breakthrough is near".
Writing in the Mail on Sunday, he suggests the Irish backstop is a 'monumental bear trap' in Theresa May's withdrawal agreement.
However, he also admits the agreement has "some good points" - such as giving certainty to EU citizens in the UK and vice versa.
He explains: "This is not a time to make the best the enemy of the good, and most MPs are in a mood to compromise, but the danger of this backstop becoming permanent is a real one and it has to be tackled."
He suggested a "legally binding guarantee that the backstop is temporary" is still needed.
However, he added: "Once we have that, my colleagues in Parliament need to recognise the strength of feeling. The whole country is tired of vacillation and delay.
"When the right compromise is offered, we should pull together behind the Prime Minister and help her to deliver our exit from the European Union on March 29."
MPs will next be given an opportunity to vote on the Brexit deal and any changes Mrs May's government secures on March 12th.
If it's rejected again, MPs will then vote on whether or not to reject a no-deal Brexit.
If politicians rule out a 'crash out' Brexit, they'll then be asked on whether they'll agree to a short delay to Brexit.
Speaking today, the UK's international trade secretary said an extension to Article 50 would be unacceptable if it was designed to thwart Brexit.
However, Liam Fox acknowledged that a short delay may be necessary in order to legislate for Brexit in the event of an agreement.
He told BBC's Andrew Marr Show: "I think that to attempt to have a delay mechanism in order to thwart the process of Brexit itself is actually politically completely unacceptable."