Problems grew after new documents linked to Jeffrey Epstein were released. These files reportedly show close connections between Mandelson and Epstein, a convicted sex offender. Many critics say the appointment was a serious mistake and has hurt Starmer’s reputation.
Removing a Labour prime minister is not easy. There is no automatic vote to remove the leader. At least 80 Labour MPs must support a challenge before a leadership contest can begin.
There is no clear replacement yet, but several Labour leaders are being discussed as possible successors.
Home Secretary Shabana Mahmood oversees immigration and law and order. Her parents are of Pakistani origin. She has gained support from the right side of the Labour Party by taking a tougher approach to border control and illegal immigration.
Health Secretary Wes Streeting is known as a strong speaker and a regular defender of the government. He has spoken openly on major issues, including the war in Gaza. Although rumours say he wants to become prime minister, Streeting has denied planning any challenge to Starmer.
Former deputy prime minister Angela Rayner comes from a working-class background and is popular with Labour members. She left school at 16 and later worked with trade unions.
Rayner resigned from government last year after admitting a tax mistake on a house purchase. However, she recently led a group of MPs demanding more transparency after the Epstein-related document release.
Andy Burnham is the mayor of Greater Manchester and a well-known Labour figure. He has served as a Cabinet minister before. However, his chances are limited because he is not currently a Member of Parliament, and by tradition the prime minister must be an MP.
Energy Secretary Ed Miliband previously led the Labour Party but lost the 2015 general election. He says he does not want to return as leader, but he remains one of the most experienced members of the Cabinet.