Keir Starmer isn't the only problem now Wes Streeting has quit, writes Leo McKinstry, centre, the lack of credible successors is (Image: Getty)Labour MPs make poor assassins. The phrase “circular firing squad” could almost have been invented for them. They are quick to plot, but slow to strike. In the case of the crisis that now engulfs Sir Keir Starmer, Labour’s chaos is compounded by the poor calibre of his likely successors. When Harold Wilson retired in 1976, the battle to be the next Prime Minister featured titans like Roy Jenkins, Tony Crossland, Denis Healey, Jim Callaghan, and Tony Benn...