Andy Burnham’s hopes of returning to Westminster were dealt a blow on Tuesday as the Merseyside MP whose seat had been named by key allies for a potential byelection said she would not stand down and backed Keir Starmer to stay in office. Marie Rimmer, the MP for St Helens South and Whiston, said the mayor of Greater Manchester had not spoken to her “in years” – and that her priority was to avoid the chaos of a leadership contest. Allies of Burnham, who hopes to seek to replace Starmer as prime minister, had said Rimmer’s seat was one possibly in contention for him to fight a byelection. But Rimmer, who has been an MP since 2015, said: “I’m not planning to stand down for anybody. I was selected by my constituency party and it’s my constituency party who decides who stands. I’ve not spoken to Andy Burnham in years and neither has he spoken to me.” Allies of Burnham said the two had in fact spoken recently.…