British Prime Minister Boris Johnson will send what he says is the UK's 'final offer' for a Brexit deal to the European Union on Wednesday, as the date for Britain's departure from the bloc looms in less than a month.

Johnson says the proposal is a 'fair and reasonable compromise,' but it's likely to face deep skepticism from EU leaders, who doubt the UK has a workable plan to avoid checks on goods or people crossing the border between EU member Ireland and the UK's Northern Ireland after Brexit.

Johnson said on Tuesday there would inevitably be some customs checks between Northern Ireland and Ireland — an idea vehemently opposed by the government in Dublin.

The British government says it will send the proposals to Brussels on Wednesday after Johnson closes his Conservative Party's annual conference in Manchester, northwest England with an election-style speech. Johnson says he will walk away from the Brexit talks if the EU refuses to 'engage' with the UK plan.

Britain narrowly voted in 2016 to leave the EU but remains deeply divided over the departure terms.

Accusing his political opponents of seeking endless Brexit delays, Johnson will tell Conservatives that Britain must leave the EU on October 31 so that 'in 2020, our country can move on.'

A Brexit agreement between the EU and his predecessor, Theresa May, was rejected three times by the UK Parliament, largely because of opposition to the 'backstop,' an insurance policy designed to ensure there is no return to customs posts or other infrastructure on the Irish border.

An open border underpins both the local economy and Northern Ireland's peace process. But Johnson and other British Brexit supporters oppose the backstop because it would keep the UK tightly bound to EU trade rules in order to avoid customs checks — limiting the country's ability to strike new trade deals around the world.

So far, the UK has floated the idea of a common area for livestock and agricultural products, plus largely untested 'technological solutions' as a replacement for the backstop.

The Daily Telegraph reported the new UK plan proposes to keep Northern Ireland in a regulatory zone with the EU for food, agricultural and industrial products until 2025. The EU has previously rejected any proposals that contain a time limit.

Johnson said late Tuesday that convincing the EU to strike a deal would not be 'a walk in the park,' but he thought agreement could be reached by the time the bloc's leaders meet for a key summit in Brussels on October 17-18.

'We have made huge progress and I hope very much that in the course of the next few days we are going to get there,' he told a reception at the Conservative conference.

Johnson says the UK can handle any bumps that come from tumbling out of the bloc without a deal, which would mean the instant imposition of customs checks and other barriers between Britain and the EU, its biggest trading partner.

But the UK government and businesses both say the disruptions would be substantial, with the flow of goods coming into Britain through the major Channel port of Dover cut in half.

Many lawmakers want to prevent a no-deal exit, and have passed a law that compels the government to seek a delay to Brexit if it can't get an agreement with the EU by October 19. Johnson says he won't do that — though he also insists he will obey the law.

In his conference speech, Johnson will say 'we can, we must and we will' leave the EU on October 31 — promising weary voters a life beyond the Brexit morass.

Whether Britain leaves the EU on October 31 or not, Johnson is likely to face the verdict of voters in an election before the end of the year.