THE next prime minister should strive to reach a Brexit deal, Theresa May has said in her final major speech in the role, as the race to succeed her entered its final stretch.

Boris Johnson and Jeremy Hunt took part in the final hustings of the campaign last night.

Offering advice to her successor, May said they should find a way to leave the European Union that was “in the national interest”.

Former foreign secretary Johnson, the favourite to become the next prime minister, has made a “do or die” pledge to leave the EU on October 31 with or without a deal.

Current Foreign Secretary Hunt has said he could delay Brexit beyond that point if a deal was in reach, but has not ruled out walking away from negotiations without an agreement.

Answering questions after her final major speech as Prime Minister, May said the “best route” for Brexit was to leave with a deal.

“I think we had a good deal, but Parliament wasn’t willing to come behind that with a majority.

“It will be for whoever succeeds me to find a way through that and I believe that the aim must still be to leave – ie to deliver on the vote of the referendum – but to do so in a way that is in the national interest.”

She defended the Irish backstop, one of the most contentious parts of her Brexit deal.

Both contenders in the race to succeed her have declared that the backstop – a contingency plan to ensure there is no hard border with Ireland – is dead and should be replaced.

However, May said: “At the heart of the Belfast Good Friday Agreement is an essential compromise that people who are Irish can live in Northern Ireland as part of the UK but on a day-to-day basis, in their business and their own personal activities, operate without any encumbrance on their operation across that border.

“I believe it’s important that we are able to sustain that into the future.”

In her speech itself, May said the 21st century could be a “pivotal point” in human history.

She cited progress in technology, societal shifts and a growing awareness of the environment.

Speaking at Chatham House in London she said: “The 21st century has the potential to be a pivotal point in human history, when economic, social and technological progress reach a combined apogee with the benefits multiplied and with everyone enjoying a share.

“It will not come about without effort. We will all have to work hard.”

The PM said she is “worried” about the state of politics.

“It has been democratic politics, an open market economy, and the enduring values of free speech, the rule of law and a system of government founded on the concept of inviolable human rights that has provided the nexus of that progress in the past.

“And a healthy body politic will be essential to consolidating and extending that progress in the future.

“It is on that score that today we do have grounds for serious concern. Both domestically and internationally, in substance and in tone, I’m worried about the state of politics.

“That worry stems from a conviction that the values on which all of our successes have been founded cannot be taken for granted.”

May added: “Today, an inability to combine principles with pragmatism and make a compromise when required seems to have driven our whole political discourse down the wrong path.

“It has led to what is, in effect, a form of absolutism.

“One which believes that if you simply assert your view loud enough and long enough you will get your way in the end.

“Or that mobilising your own faction is more important than bringing others with you. This is coarsening our public debate.”

Labour MP David Lammy described Theresa May’s speech as “hollow words”, referencing the controversial Home Office advertising campaign of 2013 which encouraged illegal immigrants to “go home or face arrest”.

“Hollow words from a PM who spent her years in office promoting Farage’s agenda with populist rhetoric, insulting EU citizens as ‘queue-jumpers’, and saying internationalists are ‘citizens of nowhere’,” he said.

“We’ll never forget the ‘go home’ vans you put on our streets.”