Arguably the most important policy position of the 10 Tory leadership hopefuls are their plans for the Irish border post-Brexit.
The controversial ‘backstop’ arrangement for the UK in the event of a no deal withdrawal would result in Northern Ireland being treated differently from the rest of the UK by remaining aligned with some rules of the EU single market.
The DUP, whose 10 MPs entered an agreement to give the Conservatives a working majority at Westminster, has repeatedly rejected the notion of Northern Ireland only customs arrangements.
However, the backstop is only intended to be used as a last resort if an overall trade and customs deal cannot be agreed between the UK and the EU before Brexit.
Boris Johnson: The ex-foreign secretary has branded the backstop a “monstrosity” that could result in the UK becoming a “vassal state of Brussels.”
Michael Gove: The environment secretary has also spoken out against the backstop, saying there must be a renegotiation of the deal with a “clear exit mechanism”.
Jeremy Hunt: The foreign secretary said he believes the EU has now realised the backstop will never be acceptable to the UK Parliament.
Dominic Raab: A “forensic change” to the backstop has been proposed by the former Brexit secretary – understood to mean replacing the entire proposal with the ‘Malthouse compromise’ (a consensus arrangement among Conservative MPs by housing minister Kit Malthouse).
Matt Hancock: The health secretary said he would seek to time limit the backstop, and proposed a new body, including Northern Ireland’s political parties, to find a way forward.
Sajid Javid: The home secretary has spoken of a new “digitised” border he believes could be operational within two years – placing no new infrastructure on the border.
Esther McVey: The former work and pensions secretary is opposed to the backstop, saying it should never have been agreed to, but does not believe the EU will renegotiate.
Mark Harper: The former chief whip is in favour of removing the backstop and replacing it with the Malthouse compromise. He said that “existing practices” around sensible cooperation would avoid a hard border.
Andrea Leadsom: The former leader of the Commons supports what she calls a “managed exit” rather than a renegotiation of the backstop – including a basic trade deal involving technological solutions.
Rory Stewart: The international development secretary has urged his rival candidates to “stop pretending” that the EU will agree to renegotiate the current backstop arrangement.
• The next Tory leader and prime minister should have an “absolute commitment” to maintaining the Union, Robin Swann has said.
The Ulster Unionist leader was commenting ahead of the voting procedure to elect a new leader of the Conservative Party.
Then candidates, each with the backing of at least eight MPs, have entered the race which involves a series of votes, with the number of candidates being whittled down until only two remain.
Beginning on June 13, the process concludes on July 22.
Ulster Unionist party Leader Robin Swann MLA said: “We would like the next prime minister to be a unionist who understands the UK is made up of four constituent parts, has an absolute commitment to the maintenance of the Union and the prosperity of all its people.
“The backstop is the problem that needs dealt with and it ultimately broke Theresa May`s premiership.”
Mr Swann added: “Her successor must deliver a Brexit which maintains the economic and constitutional integrity of the United Kingdom and ensures there is no border in the Irish sea.”
A DUP spokesperson said: “The Conservative leadership is a matter for the members of the Conservative Party. We look forward to working with the next Prime Minister to ensure that the referendum result is respected and that the United Kingdom leaves the European Union together as one nation.”