The European Union’s chief Brexit negotiator, Michel Barnier, has told Tory Party leadership hopefuls that they cannot renegotiate the withdrawal treaty to improve the backstop, saying the one agreed by Theresa May is “the only one possible”.

“A new prime minister will not change the problem. The problem is there and the new prime minister will have the responsibility with us to solve this problem,” Mr Barnier said during a conference in Slovakia on Friday.

Mr Barnier added, in comments reported by Reuters, that if the UK wanted to leave the EU in an “orderly manner”, then “the Withdrawal Agreement is the only one possible”.

The French politician has said on a number of occasions that the EU will not change the treaty, and that the only options are to cancel Brexit, accept the EU-approved deal, or leave the bloc on World Trade Organization (WTO) terms, with the Eurocrat previously advising the UK to prepare for a clean, no-deal exit.

His position has been backed by President of the European Commission Jean-Claude Juncker, who said last month: “I was crystal clear. There will be no renegotiation.”

Macron Says October Is ‘Final, Final Deadline’ for Brexit https://t.co/3bGn67k9Dh — Breitbart London (@BreitbartLondon) June 5, 2019

However, a number of Conservative Party leadership hopefuls maintain that a new leader and prime minister could persuade Brussels to eliminate or change the backstop arrangements, including Sajid Javid, Jeremy Hunt, and Michael Gove.

The recent insistence of Mr Barnier, making the statement on Prime Minister Theresa May’s last day as party leader, makes a clean Brexit more likely, given that MPs will not pass the unpopular treaty in parliament and French President Emmanuel Macron’s assertion this week that Brexit cannot be delayed any longer than October 31st.

Other candidates, notably Boris Johnson and Andrea Leadsom, have said that they are prepared to take the UK out of the EU by October 31st, without or without a deal, with Esther McVey saying she wants to ditch the treaty and leave on WTO terms.