With China, Ukraine and the future of NATO all areas of potential policy friction it will not be a quiet posting.
As the UK’s man on the ground in Washington DC, Lord Mandelson will have ready access to the Trump team.
He will be expected to charm and cajole the incoming administration at a potentially very delicate time for US/UK relations.
Lord Mandelson is unabashed about his network of connections and Downing Street sees that as a plus.
In the years since stepping back from frontline politics he has made a lot of money through the advisory firm he co-founded, Global Counsel.
But his connections and friendships with the world’s super rich have come under scrutiny too.
In 2008 Lord Mandelson’s contacts with the Russian billionaire Oleg Deripaska put him back on the front pages.
In 2023, his former friendship with disgraced financier Jeffrey Epstein hit the headlines, external.
A spokesman for the Labour peer said: “Lord Mandelson very much regrets ever having been introduced to Epstein.
“This connection has been a matter of public record for some time. He never had any kind of professional or business relationship with Epstein in any form.”
Lord Mandelson is not a baggage-free choice for a big diplomatic job.
A number of Blair-era figures have returned to the centre of power since Labour’s general election win. Not least Mr Blair’s former chief of staff Jonathan Powell who is now the UK’s national security adviser.
In Lord Mandelson, Sir Keir Starmer has picked a political figure over a diplomat or a career civil servant and Donald Trump will find himself dealing with a man at the heart of Labour’s governing family.
Lord Mandelson will be a bridge between a president and prime minister who seem temperamentally and politically miles apart.
The outgoing UK ambassador Karen Pierce is known as the “Trump whisperer” within Washington for her close contacts with the incoming president’s team.
Having whispered around the corridors of Westminster for decades, Lord Mandelson will soon be deploying his political cunning in the court of Donald Trump.
