Veteran Labour politician Peter Mandelson set to be named UK ambassador to the US

LONDON — Veteran U.K. Labour Party politician Peter Mandelson will be Britain's next ambassador to Washington, people familiar with the decision said Thursday.

Mandelson, who served in senior posts in the governments of former prime ministers Tony Blair and Gordon Brown, is expected to take up his job early next year. The announcement is expected to be made on Friday.

The current ambassador, Karen Pierce, is likely to remain in her post until after President-elect Donald Trump's inauguration on Jan. 20.

The news of Mandelson's appointment was first reported by The Times of London newspaper. It was confirmed by two people familiar with the decision, who spoke on condition of anonymity because it has not been formally announced.

Mandelson, 71, has been considered a front-runner for the job, considered Britain's most important diplomatic post - even more so with the protectionist Trump returning to office.

Mandelson was one of the key architects of Labour's 1997 return to power under Blair after 18 years in opposition. He served in Blair's government from 1997 to 2001 and as business secretary under Brown from 2008 to 2010, and in between was the European Commissioner for trade.

His trade expertise is likely to prove vital in dealing with the Trump administration, which has threatened to impose tariffs on almost all imported goods.

Prime Minister Keir Starmer said Thursday that "we have to make sure that we avoid tariffs'' with the United States.

Mandelson is also renowned as a skilled — and, to critics, ruthless — political operator. It is rare for politicians to be appointed as U.K. ambassadors — the jobs usually go to career diplomats.

Mandelson told the BBC last month that he would be ''very interested'' in giving advice on trade to whoever got the Washington job.