As the former cabinet minister sat at home trying to enjoy the last few days of relative peace before parliament reconvenes, there was a knock at the door. It was an enterprising tradesman, handing out his card. “Need any work doing?” he asked. The Tory MP declined, but the tradesman was undeterred. “We’ve got some great deals – better than Theresa May’s!” The former minister had to laugh: “You know you’re in trouble when your deal has become a punchline.”

Despite a much-needed break in hostilities, the great Brexit battle has never been far away. And while the Christmas truce came as a blessed relief to many MPs, plotting among various factions across the political spectrum has well and truly resumed.

Stopping Brexit. Leaving with no deal. Toppling May. Allowing parliament to take control. Another delay to the crucial Brexit vote. All the options are being gamed out by officials, MPs and ministers across parties and by campaigners outside parliament before a pivotal fortnight.

“This feels just like last summer,” said one influential Brexiter. “Downing Street got to a break and the temperature went down. But it won’t take much to heat it up again. In just a few days, we could be right back to where we were a few weeks ago.”

There is one key question being asked by hardline Brexiters and ardent Remainers alike: while the raw anger at Theresa May’s handling of Brexit has dissipated, have any doubters actually changed their minds about her deal?

Several MPs said there had been a far more confident tone coming from Downing St about the chances of the prime minister’s deal passing the House of Commons, though perhaps not at the first attempt. Yet no MPs said they had detected any major shift among the dozens of Tories who have already committed to voting down May’s deal. Northern Irish Democratic Unionist party MPs, whose support May needs if her deal is to pass, have again repeated their opposition.

“I have sat in meetings in which senior No 10 figures insisted that the DUP would accept the deal – even when everyone knew they never would,” said one government insider. “They have a track record of over-confidence when it comes to what MPs will support.”

No 10 and Tory whips have been working hard to win over doubters, both in European capitals and in parliament. May has been on the phone to German chancellor Angela Merkel, French president Emmanuel Macron and Dutch leader Mark Rutte, trying to argue for further concessions. Whips have been working on the “persuadables” – a group of pro-Brexit MPs worried about leaving with no deal.

Facebook Twitter Pinterest John Redwood, one of the most hardline Brexiters, was given a knighthood. Photograph: Rex/Shutterstock

Early evening drinks, with partners invited, are being held for backbenchers on Monday and Wednesday in Downing Street. “It is no doubt to celebrate John Redwood’s knighthood,” said one suspicious MP. Redwood, one of the most hardline Brexiters, was the surprise recipient of the title in the New Year honours list.

Pro-Brexit MPs, however, have not detected a major collapse in their numbers. All MPs now expect some kind of concession to be announced by Brussels and the prime minister this week, but expectations that it will be strong enough to shift the scores of MPs needed by May are extremely low.

“Downing Street has been able to control the message to some degree because no one else has been around over Christmas,” said one. “That’s where the optimism comes from, but that’s not the case any more. As soon as their claims meet reality, they crumble. That’s already happening.”

Some senior government officials admit there is a lot more work to do. “No amount of eggnog has changed the minds of the hardline Brexiteers, but the fundamentals of the argument also haven’t changed. This is a deal that can deliver for the country. There is no deal that gives them what they want,” says one.

In fact, the growing talk among both MPs and Whitehall insiders is of another delay to the Brexit vote. While Downing Street insists the vote will go ahead a week on Tuesday, some now believe the government will back an amendment that would effectively delay the vote again and give May more time to negotiate. Sceptical MPs want more legal guarantees that ensure Britain will not be tied to the EU’s customs union for ever.

Such an idea has been suggested publicly by Nikki da Costa, until recently the head of legislative affairs in Downing Street. A similar plan was being discussed before the first vote was delayed.

“The tone has improved on both sides of the negotiating table, but we don’t seem to be any closer on the substance,” said one government official. “To be honest, when we come back it will be Groundhog Day – wondering how much the vote will be lost by, whether it will be delayed and what May can then get when she heads back to Brussels … again.”

Any further delay to the vote would cause serious anger both within the cabinet and among MPs, with predictions that it would drain all of May’s remaining authority and prompt a renewed attempt to remove her, a task made much more difficult by her victory in last month’s confidence vote in her leadership.

Under party rules, she cannot face another vote for a year, so any attempt to remove her would have to rely on a mass ministerial walkout or rebellion.

“Any attempt to delay this further and all that leadership stuff will come back with a vengeance – people just wouldn’t stand for it,” said one former cabinet minister. Another senior Tory said: “Everything’s going to be fluid once the deal is voted down. The real scandal would be if they delay it again. That would be an outrage.”

Meanwhile, supporters of adopting the “Norway Plus” option, which would see Britain stay in the EU’s single market and customs union, will effectively relaunch the idea this week, with a cross-party pamphlet outlining its benefits.

As for supporters of a second referendum, everything relies on Labour shifting position and backing another public vote. That still seems some way off, with both Jeremy Corbyn and Unite union boss Len McCluskey both recently repeating their concerns about another vote.

Tories who back a second vote say that Labour’s reluctance to support it is stopping more ministers from making the leap, though some are expected to do so should May’s deal be voted down.

While Keir Starmer, the shadow Brexit secretary, is pushing for Labour to back a second referendum as quickly as possible after the Brexit vote, other senior Labour figures closer to Corbyn are far more cautious. “It seems to me that the most likely immediate action is that May will do a phoney renegotiation and then a second vote [on her deal],” said one. “In the meantime, I would have thought our objective has to be to defeat the idea of a no-deal Brexit. It still feels that there’s some further actions before we give consideration to a second referendum.”

This means the pressure from Labour’s overwhelmingly pro-Remain supporters is increasing. There are demands for a special conference on the issue, first revealed by the Observer. Thousands of members and supporters have now written to Labour’s national policy forum before a key policy meeting this week. The accounts from activists include claims of resignations and lost activists should the party not back a second vote.

So important is Labour’s position on a second referendum that campaigners are increasingly aiming their fire squarely at the party’s leadership.

The biggest Brexit poll conducted since the 2016 referendum, commissioned by the People’s Vote campaign, suggests a collapse in support for Corbyn’s party when people were asked how they would vote should Labour back or allow its MPs to support some kind of Brexit deal.

Labour polled 34% support in the YouGov poll of 25,000 people, conducted between 21 December-4 January. It puts them six points behind the Tories.

When voters were asked how they would vote should Labour MPs back a Brexit deal, its support fell to 26% – 16 points behind the Conservatives. Should Labour allow its MPs to vote however they wanted, support also fell to 26%. Campaigners argue the finding shows Labour faces losing millions of supporters by facilitating Brexit.

With so much unresolved uncertainty, even the most battle-hardened MPs are bracing themselves. “In all my years, I can honestly say this is the one time I am really not looking forward to going back,” said one Commons veteran. “We’ve all been in no man’s land for a couple of weeks, but it’s now back to the trenches.”