India, April 29 -- UK Prime Minister Keir Starmer's former chief of staff said Tuesday that he made a "serious mistake" by recommending Peter Mandelson be made UK ambassador to the United States, but denied interfering with the appointment process.

Morgan McSweeney told lawmakers on the House of Commons Foreign Affairs Committee that it had been "a serious error of judgment" to back Mandelson.

The committee is investigating how Mandelson, a scandal-tainted friend of Jeffrey Epstein, was given the key diplomatic job despite failing security checks.

McSweeney said that "the prime minister relied on my advice, and I got it wrong."

He apologised to Epstein's victims, saying, "I am sorry for any part this controversy has played in causing ...