Boris Johnson says: "Nobody wants to see a return of any kind of infrastructural or hard border" on the island of Ireland and adds that the UK government would "never" do that.

Jeremy Hunt says technology can be used to create a "soft border", but it is important that the UK is not "trapped" indefinitely in the EU's customs union.

Sajid Javid says there needs to be a time limit on the so-called backstop plan for the border, arguing that Parliament will not vote for it as it stands.

Mr Javid has previously pledged to pay Ireland for the cost of border technology.

He says it should be "perfectly possible" to keep an open border using "existing technology", with different customs arrangements either side of the border.

Chris Mason
Political Correspondent

...or not a friend to many. To loads of Conservative MPs it is the biggest roadblock to backing the deal Theresa May did.

Sajid Javid, above, talks about a time limit to the backstop - Emily Maitlis points out the EU has repeatedly said that is not a goer.

It's a reminder that after all this stuff about sorting a new PM is over, the new occupant of No 10 will face the same questions and the same parliamentary arithmetic Theresa May has faced.

Reality Check

Could the backstop question be dealt with after the UK has left the EU?

When the EU granted a further Brexit delay, it said there could be no opening of the Withdrawal Agreement - the legally binding part of the divorce deal which contains the Irish backstop plan.

It earlier set out a schedule that meant this Withdrawal Agreement would have to be agreed before any discussions on the future relationship and trade could begin.

Lead EU negotiator Michel Barnier said: "We would not discuss anything with the UK until there is an agreement for Ireland, for Northern Ireland."

Whether the EU might show any flexibility on this when faced with a new prime minister or a fresh threat of no deal remains to be seen.

The third question, from Mark in Belfast, is about how the candidates will "solve the issue of the Irish border" in the Brexit negotiations. It's been a key sticking point, especially given Northern Ireland's Democratic Unionist Party props up the Conservative government.

Chris Mason
Political Correspondent

Urgh...

Rory Stewart says: "I am committed that there would never be no deal

"It is so unnecessary and damaging. It is not even a credible threat."

Chris Mason
Political Correspondent

This is the power of live scrutiny on television, in prime time where the reaction of voters is there to see as the rhetoric gushes out. The questioner tells all five men they've done nothing to reassure her.

Foreign Secretary Jeremy Hunt says: "The reason why we need to keep no deal on the table is that we need to get a deal" - and it's a key bargaining too - but he insists it should only be a "very, very last resort".

Sajid Javid adds: "One of the fundamental mistakes we've made so far is we didn't prepare well enough, and that's why we're in this mess today."

Rory Stewart says those candidates who want to deliver a no-deal exit - of which he is not one - will have to do so against the wishes of Parliament. He demands that they explain how that can happen.

Boris Johnson says he doesn't want a "disorderly Brexit" so it is important to prepare for the prospect of leaving without a deal.

Dominic Raab, a committed Brexiteer, was eliminated in voting earlier tonight.

Chris Mason
Political Correspondent

"We didn't prepare well enough, and that is why we are in this mess today," says Home Secretary Sajid Javid - repeating a line he used in the hustings with Westminster reporters yesterday.

Chris Mason
Political Correspondent

... if you just listened to Emily and are giving us a read!

Michael Gove says he does agree that a no-deal Brexit would create "some economic turbulence".

He adds there are some parts of the country that would suffer if the UK didn't prepare properly for such a scenario.