By Mukesh 
The former chief of staff to U.K. Prime Minister Keir Starmer acknowledged on Tuesday (April 28, 2026) that he made a “serious mistake” by recommending Peter Mandelson be made British ambassador to the United States, but denied pressuring officials to ignore security concerns.
Morgan McSweeney told lawmakers on the House of Commons Foreign Affairs Committee that it had been “a serious error of judgment” to back Mr. Mandelson, whose ill-fated appointment has left Mr. Starmer fighting for his job.