A no-deal Brexit has become a very real prospect, a senior figure in UK Prime Minister Boris Johnson's government has said.

Writing in The Times newspaper on Sunday, UK Conservative MP Michael Gove said that the UK is now preparing for a no deal on the assumption that the European Union will not renegotiate former Prime Minister Theresa May's withdrawal agreement.

Gove was appointed this week by Johnson as the Chancellor of the Duchy of Lancaster and tasked with boosting preparations for the UK to leave the European Union without a withdrawal agreement.

"We still hope they will change their minds, but we must operate on the assumption that they will not. The prime minister has been crystal clear that means we must prepare to leave the EU without a deal on October 31, and I fully support this approach," Gove wrote.

"No deal is now a very real prospect, and we must make sure that we are ready," he added.

Throughout his leadership campaign, Johnson was vocal about his readiness to take Britain out of the EU without a deal, pledging to leave on October 31, the latest deadline for the UK to depart the bloc.

Johnson doubled down on that campaign commitment on Wednesday when he took office, saying that he would defy the "doubters and the doomsters," pledging to take Britain out of the EU on October 31, "no ifs, no buts."

The EU has repeatedly said that it isn't interested in reopening the Withdrawal Agreement -- the deal that May signed with the bloc in 2018 but has been repeatedly rejected in Parliament.

If he cannot negotiate a new deal with the EU, Johnson has said that he'd be willing to force Brexit through on Halloween. He has refused to rule out suspending parliament in order to do so.

Official forecasts suggest that breaking out of the bloc without any deal in place risks triggering a recession and the British pound taking a nosedive.

Speaking on Sky News on Sunday, UK opposition leader Jeremy Corbyn said he would guarantee that his Labour Party "will do everything to prevent a no deal exit" from the EU and that "we will do everything to challenge this government and we will do it at a time of our choosing."

Corbyn said he was "absolutely" gearing up for a general election and that he is "not in the slightest" bit worried about going up against Johnson, who won in Labour strongholds when he became London mayor in 2008.