LONDON (AFP) - British MPs who have long campaigned for Brexit face a dilemma - back an unsatisfactory divorce deal on Tuesday (March 12) or hold out for something better at the risk of losing everything.
Many "Brexiteers" - once known as "euro-sceptics" - have built their whole political careers on opposition to Britain's membership to the EU, and success is tantalisingly close.
But few have any enthusiasm for Prime Minister Theresa May's proposals for leaving on March 29, hammered out over months of talks with the European Union.
They fear the deal will leave Britain a "vassal state", with its plans for a transition period and the "backstop" plan for the Irish border, and chafe at the £39 billion (S$69.90 billion) exit bill.
But if they reject it, MPs could vote on Thursday to delay Brexit - giving further time for pro-Europeans to try to undermine the whole process.
Environment Secretary Michael Gove, a leading campaigner for Brexit in the 2016 referendum, admitted the deal was a compromise but urged his colleagues to get behind it.
"None of us Leavers should try to make our perfect Brexit the enemy of the common good," he wrote in the Daily Mail newspaper.
But the euro-sceptic Daily Telegraph said it would be "the most humiliating treaty this country ever agreed to".
Some believe a better deal is still possible before Britain's scheduled exit from the EU - or say they are ready to walk away without an agreement.
CORE OF HARDLINERS
When Mrs May's deal was first put to the House of Commons in January, more than one-third of her Conservative MPs - 118 out of 306 - joined opposition parties to vote against it.
The 10 MPs in Northern Ireland's Democratic Unionist Party (DUP), which props up Mrs May's government in Parliament, also voted it down.
The Prime Minister has now secured some guarantees on the hated backstop arrangement, intended to keep open the Irish border.
But they fall short of the changes to the treaty text itself that many lawmakers had demanded.
The Brexiteers are not a homogenous group, and there is a hard core who are unlikely to be swayed - enough to scupper the deal.
When Mrs May asked MPs last month for more time to negotiate, 20 Tories voted against her because she had raised the possibility of delaying Brexit if she failed.
They include Mr Bill Cash, a rebel who took on former prime minister John Major over the EU's Maastricht Treaty.
Mrs May has used various arguments to persuade MPs to back her deal, warning both that defeating it risks a "no deal" Brexit, or that Britain may never leave the EU at all.
Fear of the economic damage of withdrawing with no deal prompted pro-European ministers to threaten to resign if she did not allow MPs to vote to delay Brexit as an alternative.
But many Brexiteers believe these worries are overblown.
Mr John Longworth, co-chairman of the campaign group Leave Means Leave, is among those who call for Britain and the EU to agree to a basic trade deal and exit as planned on March 29.
He drew cheers at a packed meeting in Westminster on Monday, where many people shouted "shame" at the mention of Mrs May's deal.
Mr Longworth accused both London and Brussels of failing to take this bare bones option seriously "because they're both determined to frustrate and reverse Brexit".
Critics of this plan, however, point out that it would still require an EU deal of some sort.
Other Brexiteers meanwhile believe Britain must keep "no deal" as a bargaining chip - and believe that even at this late stage they can still get a better deal.
Former Brexit minister David Davis told the BBC on Sunday that this week's votes were merely "stepping stones in a negotiation".