Appointment of next UK ambassador to the US suspended

The row began in late April when Downing Street announced General Gwyn Jenkins, vice chief of the Defence Staff, would replace Sir Tim as national security adviser. It did not say what new role Sir Tim would take up but Mr Sunak did not deny reports he would become Britain’s top envoy in the US.

When asked by political reporters on a plane to Warsaw, Mr Sunak said “ambassadorial or diplomatic appointments are always made in the usual way” and added: “It’s entirely normal for those to be made in advance… entirely in keeping with precedent because ambassadors’ designate often go and acclimatise themselves and build relationships before they formally start”.

The current ambassador Dame Karen Pierce is expected to leave next year after her appointment was extended for another 12 months to make up for Covid-related disruption at the beginning of her term.

“I think the next ambassador will arrive in early 2025, and I will stay till then,” she reportedly told a recent diplomatic gathering at the Washington embassy.

Sources say the Foreign Secretary, Lord Cameron, had assured his Labour shadow, David Lammy, that such a significant official appointment would not be made in the run-up to the election.

But it is understood Downing Street ignored Lord Cameron’s concerns and decided to press ahead with the appointment. Whitehall sources said No 10 wanted to announce General Jenkins’ appointment as the first NSA from a military background to reinforce their commitment to security, a key Tory election theme.

It is understood that if Labour won the election, Sir Keir Starmer would revisit Sir Tim’s appointment and might instead choose another candidate. At the very least it is expected that he would begin a new recruitment process.

The extension of Dame Karen’s term until next year would give Labour the chance to choose her successor after the outcome of the US election in November is known.