His trade policy experience, including as an EU trade commissioner, would be “really important” at a time when Trump has threatened to introduce new tariffs, she told Sky News.

She added: “We need someone as the next ambassador to the US who is going to be able to promote our economic and security interests with one of our closest allies, and so I think he is a really good fit for the job.”

In November, Lord Mandelson said that he would be “very interested” in giving advice on trade to whoever got the job.

The former MP for Hartlepool had told the BBC that he was “more in favour of a new relationship rather than a special one” with the US, but that nobody had spoken to him about the job.

More recently he lost out to be the next chancellor of Oxford University to former Conservative leader Lord William Hague.