Prime Minister Boris Johnson will on Wednesday unveil his final Brexit offer to the European Union and make clear that if Brussels does not engage with the proposal, Britain will not negotiate further and will leave on October 31.

In his closing speech to his governing Conservatives’ annual conference, Johnson will stick to his hard line on Brexit, offering the party faithful the first details of what he will describe as his “fair and reasonable compromise”.

With less than a month until Britain is due to leave the EU, the future of Brexit, the country’s biggest trade and foreign policy shift in more than 40 years, is uncertain. Britain could leave with a deal, without one or not exit at all.

Johnson, who says Britain will leave the bloc on October 31 no matter what, will tell the conference he will send his proposal to Brussels, an attempt to secure a deal to smooth the country’s departure and avoid a potentially damaging no-deal Brexit.

“My friends, 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,” he will say, according to extracts released by his office.

“Let’s get Brexit done on October 31 so in 2020 our country can move on.”

More than three years after Britain voted to leave the EU in a 2016 referendum, Brexit talks are at an impasse.

Johnson has been firm that the October 31 deadline will be met but parliament has put roadblocks in his way passing a law that requires the prime minister to request a Brexit delay if he fails to secure an acceptable deal at an EU summit on October 17.

The EU has repeatedly asked Britain to come up with “legal and operational” proposals for the changes Johnson wants to a deal his predecessor negotiated with the bloc last year.