Boris Johnson will set out details of his “final” negotiating offer to the EU on Wednesday in pursuit of a “fair and reasonable” Brexit compromise.
The prime minister will address the Tory conference before submitting new proposals, intended to form the legal text of a new Brexit deal, to Brussels.
Only by leaving the EU on 31 October can the UK “move on”, he will argue.
Tory Chairman James Cleverly said the UK had been “flexible and pragmatic”, and now the EU must be the same.
On the eve of his speech, Mr Johnson told a conference fringe meeting in Manchester, hosted by the DUP, that he hoped to reach a deal with the EU over the course of “the next few days”.
Later, he will claim the public will no longer be “taken for fools” by those who want to delay or block the process.
The government has insisted it will not negotiate a further delay beyond the Halloween deadline, saying this would be unnecessary and costly for the UK.
However, under the terms of a law passed by Parliament last month, the PM faces having to request another extension unless MPs back the terms of withdrawal by 19 October – two days after a summit of European leaders.
On Tuesday, Mr Johnson dismissed leaked reports that customs posts could be set up on either side of the border between Northern Ireland and the Republic of Ireland.
He said suggestions the UK wanted “clearance zones” for goods as part of a package of alternative arrangements to replace the Irish backstop were wide of the mark.
While he conceded some customs checks would be needed as the UK leaves the EU’s customs union and single market, he said technology could keep them to an “absolute minimum”.
Speaking to BBC Radio 4’s Today programme, Mr Cleverly appeared to put the ball in the EU’s court.
“We have been in negotiating for some while,” he said. “The UK has been flexible, but a negotiation means both parties need to be flexible.
“What we need to see now is the EU be flexible – and if they can be pragmatic and flexible, we can leave with a deal on 31 October. But we are going to leave on 31 October whatever.”
‘Big move’
Irish Fine Gael senator Neale Richmond told Today that the PM’s plans were a “big move” from the withdrawal agreement made by Theresa May.
Mr Richmond said, under the plan, Northern Ireland would leave the customs union and “come out of the single market in all areas, apart from agri-food products and industrial products, and indeed it only stays in those areas for four years”.
This, he added, would require “additional checks” on the island of Ireland – something he described as “extremely disappointing”.
But BBC Northern Ireland political editor, Mark Devenport, said sources in the Democratic Unionist Party had indicated they were supportive of the proposals and had been “kept informed” throughout their development.
The BBC’s political editor Laura Kuenssberg said while the detail of the government’s proposals is not yet clear, there is a “real expectation and belief” in No 10 that “this is now the crunch point”.
She said: “This is the moment…where the EU will have to respond and say [either] there is something that is a basis of a deal here, or not.
“And what Boris Johnson is trying to suggest is if the answer is not, then for him, that means no-deal.”
In his keynote speech to the party faithful in Manchester – his first as prime minister – Mr Johnson will unveil what he hopes will be the basis of a compromise that can win the backing of MPs.
And BBC assistant political editor Norman Smith said it was particularly important Mr Johnson secured the support of the Democratic Unionist Party’s 10 MPs.
He said: “I think it is very clear this deal is not going to fly unless Boris Johnson can bring the DUP along with him… one way or another he has to make sure they’re on board.”
Speaking in Manchester, Mr Johnson will suggest voters are “desperate” for the country to focus on other priorities and will contrast his determination to leave on 31 October with the “years of uncertainty” that he says would result from a Labour government promising another referendum.
“What people want, what Leavers want, what Remainers want, what the whole world wants – is to move on,” he is expected to say.
“I am afraid that after three-and-a-half years people are beginning to feel that they are being taken for fools.
“They are beginning to suspect that there are forces in this country that simply don’t want Brexit delivered at all.
“And if they turn out to be right in that suspicion then I believe there will be grave consequences for trust in democracy.
“Let’s get Brexit done on October 31 so in 2020 our country can move on.”
‘Respect the vote’
Ahead of Wednesday’s speech, No 10 insisted if the EU did not engage with the UK’s offer there would be no further negotiations until after it had left on 31 October.
“The government is either going to be negotiating a new deal or working on no deal – nobody will work on delay,” a senior No 10 official said.
Analysis by Katya Adler, Europe editor
The EU needs to see the precise details of Boris Johnson’s proposals, but the direction of travel that has been coming through is different.
The very idea of customs check between Ireland and Northern Ireland, the promise of the use of technologies to ease the process that haven’t yet been tried and tested, or don’t even exist yet…that is a big no-no for the EU.
The bloc will look at the proposals carefully. They need to try as they do want a deal, and also they need to be seen to be trying.
But it is fundamentally misunderstanding the EU if the prime minister thinks at this stage the 26 EU leaders will turn round on the Irish prime minister and say: “Listen, you are going to have to accept this because we just want to have a deal.”
It is also fundamentally misunderstanding the German Chancellor Angela Merkel, her attachment to EU unity and the integrity of the single market.
And also it is misunderstanding that the EU sees this in a bigger picture. If suddenly now they were to back down to all of the prime minister’s demands how would that look to other trade partners across the globe.
So EU leaders will be very careful not to rubbish the prime minister’s ideas, to talk about them as a basis for an agreement, but if it is take it or leave it, they will be leaving at this point.
Mr Johnson’s conference speech is set to clash with Prime Minister’s Questions, which is taking place at 12.00 BST.
Normally the Commons goes into recess for the Tory conference, but MPs voted against this amid the bitter fallout from the government’s unlawful prorogation of Parliament.
Foreign Secretary Dominic Raab will deputise for the prime minister, facing the shadow home secretary Diane Abbott over the despatch box.
Source: BBC