The prospect of a trade war between the UK and the EU has edged closer, with Ireland giving the clearest hint yet that Brussels plans to suspend the entire trade deal struck last December if the British government suspends the Northern Ireland Brexit protocol.

The Irish foreign minister, Simon Coveney, accused the UK of “deliberately forcing a breakdown” in negotiations over Northern Ireland, adding that there was still time to step back from the brink.

“The trade and cooperation agreement that was agreed between the British government and the EU was contingent on the implementation of the withdrawal agreement, which includes the protocol.

“One is contingent on the other, and so if one has been set aside, there is a danger that the other will also be set aside by the EU,” he told RTE on Sunday.

His comments confirm speculation that the EU will not dwell on its options if the UK triggers article 16 of the Northern Ireland protocol, but will instead deploy measures in the wider Brexit withdrawal agreement that allow cross-retaliation.

The EU would have to serve the UK with 12 months’ notice, but it would have a devastating impact on British business, industry leaders warned. Shane Brennan, head of the Cold Chain Federation, said businesses would be “sacrificed” with “a near prohibition on UK food exports”.

Coveney’s comments come amid heightened expectation that article 16 will be triggered by the UK after the Cop26 climate crisis summit in Glasgow ends on Friday.

The Sunday Telegraph reported that the UK has begun work on a post-article-16 scenario, with plans to pull funds from the Horizon Europe research programme and go it alone with alternatives.

Coveney said there was still time for the UK to pull back from the brink, but that the EU felt that every time it offered an olive branch to the UK, the response of the British was to harden its position and “constantly raise new problems”. “You have to ask yourself the question, ‘Why are they doing that if they’re acting in good faith?’”

Ireland’s European commissioner, Mairead McGuinness, said on Sunday that suspending the trade deal would be “very severe and something the EU would want to prevent”. However, she said patience with the UK was wearing thin.

“Europe cannot stand by if article 16 is triggered [and ask], ‘What next? What does this mean?’ All of the work we’ve done as a commission is to try and solve problems, not to create them. But we have to be very firm as well,” she said. “If Lord Frost is entering the room with article 16 in his pocket, not willing to actually negotiate, we have to ask ourselves, ‘Do we continue on that basis?’”

The row is also fuelling fears that a collapse in talks will result in pressure on the Dublin government to impose customs and standards checks on the island of Ireland. McGuinness gave assurances that the EU would not make such a demand. “There will be no border on the island,” she said. “There’s a huge sensitivity around this.”

Talks between the EU and the UK enter their fourth week this week, with the Brexit minister, David Frost, to meet his counterpart, Maroš Šefčovič, on Friday.