- Video report by ITV News Correspondent Peter Smith
The Irish foreign minister has told ITV News it is a "deal-breaker" there was no time deadline on a backstop once the UK leaves the European Union.
Simon Coveney told ITV News the backstop "needs to be there unless, or until, something better comes along".
He said the backstop was a form of insurance for both sides, likening it to a household taking out fire cover.
The controversial border "backstop" is being touted as a temporary solution on avoiding a hard border on the island of Ireland. It would ensure an open Irish border after the UK leaves the EU until a permanent solution is found.
Both Britain and Ireland agreed in December 2017 that the backstop must maintain a cross-border cooperation; support the all-island economy and protect the Good Friday peace agreement.
What they have yet to agree on is how this will be maintained. The EU want a backstop that would mean Northern Ireland remaining in the customs union and parts of the single market. But the UK are not happy with this solution as this would essentially separate the UK and Northern Ireland with a customs border down the Irish Sea.
Earlier, a source told ITV News Political Correspondent Paul Brand that Brexiteers want a legal guarantee the backstop can be terminated at Britain's will.
With both sides standing firm on the issue, Mr Coveney told ITV News that it is unlikely a Brexit deal can be done in time for next week's EU summit.
Mr Coveney said: "It is a deal breaker. We need to insure that we can reassure communities in the island of Ireland that they're not going to face the corrosive impact of a physical border reemerging on the island of Ireland, bringing back memories of the past, the requirement of security around border checks and so on.
"We have 300 road crossings between Ireland and Northern Ireland. It's a 300 kilometer border. The idea that we would try and stop commercial traffic crossing that when you don't even know when you're crossing the border today because it's so seamless."