Andy Burnham’s decision to appear at a progressive rally alongside prominent Green and Liberal Democrat figures has sparked anger among some Labour MPs, who have accused him of undermining their local election message. The Greater Manchester mayor, who is seen as one of the most likely challengers to Keir Starmer, will be speaking at the Change:Now event this month organised by the left-wing group Compass. Compass’s founder, Neal Lawson, has long campaigned for a cross-party progressive alliance but is also a prominent supporter of Burnham. Two other Labour MPs, Clive Lewis, who has offered to give up his seat for Burnham, and Miatta Fahnbulleh, the communities minister, are also due to speak at the event. Other speakers include Caroline Lucas, the former Green party leader; James Meadway, head of the Green-aligned thinktank Verdant; Vince Cable, the former Liberal Democrat cabinet minister; and the Lib Dem MP Roz Savage.…