A Brexit deal looks imminent – but will Boris Johnson be able to sell it to the Conservatives?

With just hours to go until Christmas, it was only natural that Downing Street would want to give the beleaguered public an early present in the form of a prospective Brexit deal.

With millions more people set to be placed under Tier 4 Covid restrictions and queues of lorries at Dover prompting panic buying in supermarkets, here, finally, was a glimmer of good news.

Yet as the UK and the EU continue to finalise the small print on what is expected to be an imminent agreement, it remains to be seen whether Boris Johnson will be able to sell it to a Conservative Party that has spent the last 40 years at odds over Europe.

The mood among Tory Brexiteers on Wednesday night was described as "sceptical and suspicious" as the world awaited a plume of white smoke over Brussels.

Already wound up by the announcement that more constituencies will be placed into the highest band of coronavirus measures on Boxing Day, seasonal goodwill between MPs and Number 10 is in notably short supply.

As one prominent Tory leaver told The Telegraph: "Like everyone else, I don't trust Downing Street an inch right now. Obviously we will have to wait until any deal is published, but what we cannot have from the Prime Minister is another cop out.

"The agreement on fish is going to be hugely significant because it has nothing to do with a  trade deal – it's about our territory."

It certainly did not bode well that a French official had gone around briefing anyone who would listen that "the British made huge concessions" in the last 48 hours, "mostly on fishing".

Former Brexit Party leader Nigel Farage was quick out of the traps, tweeting that the Government wanted a "Christmas Eve announcement to hide the fisheries sell-out".

The influential European Research Group (ERG) of Brexiteer Tory MPs is expected to keep its counsel on any deal until members have had a chance to go over the details with a fine-toothed comb.

The Tory MP Sir Bill Cash will lead a "star chamber" of Brexit lawyers including Martin Howe QC in poring over the legal text before giving a verdict to MPs ahead of a vote, expected to take place on December 30. Sir Bill has acted as a conduit between Number 10 and the ERG in recent months.

Writing in The Telegraph earlier this month as negotiations went down to the wire, Mr Howe, a respected barrister specialising in EU law and intellectual property, appeared sceptical about the value of zero tariffs and quotas, pointing out that they favoured the EU more than the UK because of the bloc's huge trade surplus.

He suggested the real acid test of any agreement would be "whether we succumb to a deal requiring the UK to keep or follow EU laws in the years ahead, thus negating the very principle of Brexit – taking back control and giving British people the democratic power to make and change our law."

Pointing out that "Red Wall" voters gave Mr Johnson his 80-seat majority "on the promise that he would deliver a Brexit that takes back full control of our laws and full control of our fishing waters", he warned: "A deal that lets them down on either will destroy their trust."

While Brexiteers are likely to be very receptive to an independent arbitration mechanism replacing any ongoing ECJ involvement in disputes, the merest sniff of  compromise on fishing promises to open a significant can of worms.

They will demand nothing less than a deal that they can tell their constituents "unarguably" delivers on sovereignty for Britain and is a significant departure from Chequers, the deal that proved to be Theresa May's downfall.

Mr Johnson will also be keen to be able to argue that he has managed to deliver something far superior to his predecessor's negotiation if he is to survive where those before him have failed.

Having been unequivocal about "getting Brexit done", the Prime Minister faces his own political cliff edge if he is seen in any way to have conceded too much to Brussels – a miscalculation which also proved to be the undoing of John Major and David Cameron.

Little wonder, then, that his Conservative colleagues are already beginning to question how little time they will be given to scrutinise whatever he and his EU sherpa David Frost have managed to secure across the water. The Government has already made clear that it wants the deal to pass through both Houses and be given Royal Assent in one day.

The irony of the fast-tracked move being orchestrated by Jacob Rees-Mogg, the Leader of the House of Commons and a former chairman of the ERG, has not been lost on backbenchers.

As one veteran MP put it: "The Government will probably only publish the text after the weekend, giving us very little time to read it before forcing it through the lower and upper chambers.

"Jacob will acquiesce to all this, despite being the man who would have demanded a full interrogation had he not been promoted to Cabinet.

"And it will go through because Labour will almost certainly vote for it – but that doesn't mean it won't end up splitting the party."