PRIME Minister Andy Burnham rejected calls to set a maximum workplace temperature by a coalition of unions and climate activists today, as the Met Office predicted this summer will become Britain’s warmest on record. The Heat Strike campaign called on Labour to set a national maximum indoor working temperature of 30°C, dropping to 27°C for those doing strenuous work. Unions have been calling for a national maximum working temperature since 2008. Earlier this year, government advisers recommended a maximum working temperature be implemented after the Climate Change Committee warned that Britain is “built for a climate that no longer exists” in its report last month. Petitions for a maximum working temperature have topped 180,000 signatures.