LONDON — The ex-civil servant behind the decision to approve Peter Mandelson’s appointment as British ambassador to Washington says he felt political pressure to rush through the appointment despite security concerns.

Olly Robbins, former head of the Foreign Office, was fired by Prime Minister Keir Starmer last week. He told the House of Commons Foreign Affairs Committee on Tuesday that there was an “atmosphere of pressure.”

He said there was “a very, very strong expectation” that Mandelson “needed to be in post and in America as quickly as possible.”

Starmer is facing calls to resign over the revelation that Mandelson was given the crucial diplomatic post despite failing security checks.