LONDON (Reuters) – British Prime Minister Boris Johnson said he would rather find a negotiated settlement to post-Brexit trade problems in Northern Ireland but if the government does escalate its dispute with Brussels it will do so in an appropriate way.

Relations between Brussels and London have soured in recent weeks after Britain, unhappy with the deal it signed up to in 2020, threatened to trigger an emergency clause known as Article 16, potentially leading to a trade war.

However London and the European Union agreed last week to intensify efforts to solve the trade issues stemming from the Northern Ireland Protocol, after Brussels said it welcomed Britain’s “change in tone”.

In a speech late on Monday that was largely about the United Nations COP26 climate summit, Johnson said that he would “rather find a negotiated solution to the problems created by the Northern Ireland Protocol, and that still seems possible”.

“But if we do invoke Article 16 – which by the way is a perfectly legitimate part of that Protocol – we will do so reasonably and appropriately, because we believe it is the only way left to protect the territorial integrity of our country, and meet our obligations to the people of Northern Ireland under the Belfast (Good Friday) Agreement,” he said.

Were Britain to trigger Article 16, Brussels will have to decide how to respond, and its approach will likely depend on how far London goes in trying to use the mechanism as the start of a much broader renegotiation.

The European Commission’s Maros Sefcovic said on Monday he was “absolutely convinced” Britain and the European Union could break their impasse over post-Brexit trade arrangements but he remained concerned about London’s “rhetoric and action”.

(Reporting by Kate Holton, Editing by Kylie MacLellan)