Nigel Farage has said he would be willing to help incoming ambassador to the US Lord Mandelson negotiate with the Trump administration.

Labour peer Lord Mandelson has indicated he believes the Reform UK leader, a friend of Mr Trump, could serve as a link between the British Government and the Republican president-elect.

But Downing Street would not be drawn on whether Sir Keir Starmer would like Lord Mandelson to work with Mr Farage, saying when asked only that the Prime Minister had “already started to begin to build a relationship with President-elect Trump”.

Mr Farage has previously offered to use his relationship with Mr Trump and his team to act as a bridge between them and the UK Government.

He told The Telegraph he would be willing to work with people in the Labour Party if it was in the “national interest”.

“I am no fan of any of the people in the Labour Party, but if it is in the national interest I have always thought I could be a useful asset if they want to use that – but if they don’t, more fool them,” the Clacton MP said.

Mr Farage said he could help with talks on trade, tariffs, intelligence-sharing and countering terrorism because “a lot of the members of the president’s cabinet are friends of mine, and many of them long-term friends”.

He said: “I know these people, and in terms of trade, in terms of defence and in terms of intelligence, the US is our most important relationship in the world – forget Brussels.”

Nigel Farage and Reform UK treasurer Nick Candy with Elon Musk at Mar-A-Lago, the Florida home of US President-elect Donald Trump (Reform UK/PA)

He said free trade deal talks were likely to be done sector by sector.

“I would help even if it is to the Government’s benefit because it is in the national interest. But they are so split they might not want to take up my offer.”

Lord Mandelson will take up the role in early 2025.

His trade experience is seen as a strength amid concerns over what the second Trump presidency could mean for the UK, with the Republican politician having pledged to introduce wide-ranging tariffs.

However, the Labour grandee’s past remarks about Mr Trump – who he once described as “little short of a white nationalist and racist” – may yet plague attempts to foster close US-UK relations.