With less than 48 hours to go in the sizeable job of convincing a fractured UK Parliament to vote for Brexit, the hard-wrung deal is likely to be precious to Prime Minister Theresa May.

But she won't be fondling the pages of the deal cooing: "It's mine. My own. My Brexit".

Those are the words of actor Andy Serkis, who has reimagined his portrayal of Gollum from Lord of the Rings in a campaign to push for a so-called People's Vote — a second referendum — and ultimately remain in the European Union.

Key points: Anti-Brexit campaigners release video lampooning Mrs May as Gollum with her "precious" deal

Anti-Brexit campaigners release video lampooning Mrs May as Gollum with her "precious" deal A vote on Brexit is scheduled in UK Parliament for Tuesday (local time) but it is unlikely to pass

A vote on Brexit is scheduled in UK Parliament for Tuesday (local time) but it is unlikely to pass A rejection of the deal could open up the UK to more negotiations or leave it to hard crash out of the EU next March

With the parliamentary vote nearing, Serkis lampooned Mrs May in a video released online, dressing himself in a grey wig, earrings and lipstick and supposedly sitting in the gloom of No. 10 Downing Street fighting with himself over Brexit.

"This is it. Our deal," he says as Mrs May.

"We takes back control — borders, laws, blue passports."

In the video, the conflicted Prime Minister rallies against the "stupid tricksy remainers" who "want something else".

"This is the only deal! Juicy and sweet. We wants it."

Mrs May's good side argues that her friends: "told us they hates the deal. All of them hates it. They wants a people's vote."

"You don't have any friends," she replies.

It is supporters Mrs May needs ahead of the parliamentary vote.

Politicians on both sides of Parliament — including in Mrs May's Conservative Party — have criticised the agreement brokered with the EU, making its passage through Parliament on Tuesday (local time) unlikely.

Even pro-Brexit protesters turned out in their thousands on Sunday angry with the Prime Minister for not going far enough to untangle the UK from the EU.

Demonstrators for a hard Brexit marched through central London on Sunday for a "Brexit betrayal" rally organised by Britain's eurosceptic United Kingdom Independence Party (UKIP), and hosted far-right activist Tommy Robinson as a speaker.

The "Brexit betrayal" protest was organised by eurosceptic party UKIP. ( ABC News: Lincoln Rothall )

In the east of the city, the People's Vote group held their own rally calling for a second referendum on EU membership in response to Mrs May's deal.

The Sunday Times reported Mrs May was expected to say on Monday (local time) that she was delaying the vote to make a last-minute dash to Brussels to appeal to the EU to improve the deal.

But speaking on Sunday, Brexit Minister Stephen Barclay told BBC TV: "The vote is on Tuesday, that is what we are focused on."

"The risk for those who say simply go back and ask again, the risk is that isn't necessarily a one-way street, the French, the Spanish and others will turn round, if we seek to reopen the negotiation, and ask for more," he added.

If the Parliament rejects the deal, the UK will have to pick from a handful of bad options to salvage Brexit, with the March deadline for leaving the EU fast approaching.

Protesters took to the streets in central London to march against fascism and Brexit. ( ABC News: Lincoln Rothall )

ABC/Reuters