Andy Burnham now has a route back to parliament after a Greater Manchester MP announced he would stand down, triggering a byelection, and putting Burnham in contention to become the next Labour leader. The Greater Manchester mayor has been seeking to return to parliament for months, but was blocked by Keir Starmer from running in the Gorton and Denton byelection at the start this year, to the anger of his supporters inside the party. The decision by Josh Simons, the MP for Makerfield, which Labour holds with a majority of just over 5,000, paves the way for Burnham to be selected by Labour’s ruling national executive committee, which prevented him last time. The prime minister’s authority has been critically undermined in recent days after an angry response from Labour MPs to last week’s local and devolved elections, including the resignation of the health secretary, Wes Streeting , and around 100 MPs calling for him to go.…