Given how hated Keir Starmer was, most people expected Andy Burnham’s government to be more popular than what came before it. The question was how much more popular Burnham would be, and if he’d be able to sustain these gains in the long run. We now know Labour has experienced a bump from Burnham taking over. According to the pollsters, however, the ‘Burnham bounce‘ appears to be all bounced out. Exclusive: The “Burnham bounce” has ended just weeks after the new prime minister entered Downing Street, leading pollsters have said, as they warned there would be no point in Labour calling…