Backsliding on climate action would drive the Labour party into political obscurity, Zack Polanski has warned, as trade union leaders said more drilling in the North Sea would not help UK workers. The Green party leader, speaking to the Guardian as searing heat swept the country for the second time this year, urged Andy Burnham – widely expected to be the UK’s next prime minister – to be bold on climate justice. He said any move to water down the party’s commitments would have dire consequences at the ballot box. “Half measures or backsliding on climate action would be a...