LONDON (AP) — British Prime Minister Keir Starmer conceded Monday that he had lost the support of his rank and file Labour party members in Parliament and that he will be stepping down as soon as his successor as party leader is chosen, possibly as soon as the middle of July. Andy Burnham , the former mayor of Greater Manchester whose resounding victory in a special U.K. election last week set in motion Starmer’s resignation, has confirmed that he will put himself forward to be his successor.