Brexit talks have ended in fresh deadlock as the UK warned of "significant gaps" in the dispute over Northern Ireland trade rules.
Brexit Minister Lord Frost met his EU counterpart Maros Sefcovic in Brussels on Friday amid an ongoing row over fishing rights and UK demands to tear up Boris Johnson 's deal.
Speculation has been mounting that the UK will act to suspend parts of the contentious trading arrangements without EU agreement by triggering Article 16.
But Northern Ireland Secretary Brandon Lewis insisted that the explosive move was "not inevitable".
The UK wants to rewrite a key part of the Brexit deal known as the Northern Ireland protocol, which was intended to prevent a hard border on the island of Ireland by effectively keeping Northern Ireland in the single market.
Instead a trade barrier was created in the Irish Sea for goods coming from Great Britain, creating red tape and delays for businesses in Northern Ireland.
Lord Frost said progress had been “limited” and EU proposals to cut down on bureaucracy “did not currently deal effectively with the fundamental difficulties in the way the Protocol was operating”.
He warned the UK could still trigger Article 16, which would allow parts of the deal to be suspended, but it would not happen immediately.
Ahead of the meeting, he said: "We're not going to trigger Article 16 today, but Article 16 is very much on the table and has been since July.
"If we can reach an agreement on the protocol that provides a sustainable solution, then that's the best way forward."
Lord Frost has previously said the dispute would be settled "one way or another" this autumn.
But Mr Sefcovic accused the UK of failing to engage with the EU offer and warned that triggering Article 16 would have “serious consequences”.
He said: “This was a big move by us. But until today, we have seen no move at all from the UK side. I find this disappointing and once again, I urge the UK government to engage with us sincerely."
He added: "Let there be no doubt that triggering Article 16 – to seek the renegotiation of the Protocol – would have serious consequences."
Mr Lewis insisted the UK had not made a decision on whether to suspend parts of the deal, saying: "It's not inevitable at all.
"Our legal position is that the conditions have already been met for us to trigger Article 16. I think it's self-evident that we don't want to do that, otherwise we would have already done it. And we haven't done it because we want to come to an agreement with the EU.
No 10 said there no set timescale on how long talks will drag on, and Lord Frost will meet Mr Sefcovic again in London next week.
