Agreeing a post-Brexit free trade deal between Britain and the United States will take “some time”, US Secretary of State Antony Blinken has warned.

Mr Blinken said President Joe Biden’s new trade negotiator, Katherine Tai, would be taking time to review the discussions that had taken place with the Trump administration before progressing with the talks.

In an interview with the BBC Radio 4 Today programme, he stressed the importance the president placed on ensuring that the gains of the Northern Ireland peace process were maintained.

Mr Blinken, who has been in London for the meeting of G7 foreign ministers, said he believed the US and the UK were “profoundly in sync”.

However he said that the US wanted to ensure any trade agreement would benefit American workers and their families.

“Our trade negotiator just got on the job, so she’s taking the time to go back and review everything that was discussed and that’s going to take some time,” he said.

“We want to make sure that, whether it’s with the United Kingdom or anyone else, any agreements reached are consistent with the principles that President Biden has established to focus on making sure that these agreements really advance the wellbeing of our workers and their families. That’s our focus.”

Compliance is compliance and what we don't know is whether Iran is prepared to make the same decision and to move forward

With continuing tensions in Northern Ireland over the implementation of the Brexit “divorce” settlement, Mr Blinken said the US was “very focussed” on ensuring the Good Friday Agreement was maintained.

“We want to make sure that, whether it’s with the United Kingdom or the EU, whether it’s anything we’re doing, that we make sure that the tremendous gains from the Good Friday Agreement are sustained and that the economic as well the political wellbeing of Northern Ireland is taken fully into account,” he said.

On Iran, Mr Blinken said the US had shown its “seriousness and purpose” in seeking to strike a new nuclear deal after Donald Trump tore up the internationally agreed Joint Comprehensive Plan of Action (JCPOA).

However, he said Tehran had to show it was willing to comply with the terms of the agreement – intended to curb its ability to develop a nuclear weapon – amid concerns it was close to achieving a “breakout” capability.

“Compliance is compliance and what we don’t know is whether Iran is prepared to make the same decision and to move forward,” he said.

“Right now, unfortunately, Iran has itself lifted many of the constraints imposed on it by the agreement because we pulled out, and it is now getting closer and closer again to that point where its breakout time is going to be down to a few months and eventually even less,” he said.

“So there’s nothing naive about this. On the contrary, it’s a very clear way of dealing with a problem that was dealt with effectively by the JCPOA and we’ll have to see if we can do the same thing again.”