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.

Coalition campaigner Liam Geary Baulch said: “Everyone is feeling the effects of the climate. The government must protect workers when it’s too hot to work and safeguard everyone’s future. 

“The petitions show people are scared. These heatwaves are causing a national health and safety emergency. That’s why we are urging the PM to put the brakes on now, to stop accidents and save lives. 

“Until there’s a clear plan to protect everyone from the extreme heat, it’s up to us to keep our colleagues and community safe by removing ourselves from unsafe workplaces. 

“That’s why we’re supporting the bus drivers voting to strike when it’s too hot to work. We’re cooler together, join your union and join the Heat Strike.”

More than 1,500 Unite bus drivers are set to begin several days of heatwave strikes this Friday.

Their employer, Arriva North London, has allegedly failed to act on complaints about working in extreme heat.

The union says that the firm’s use of air-cooling systems, rather than more effective air-conditioning, has seen 50°C cab temperatures reports.

A north London bus driver, who voted to strike, said: ”Driving a bus in these heatwaves is like driving a greenhouse. Some drivers who are bringing in their own thermometers reported 50 degrees in cabs last time. This week will be unbearable.

“They’re asking us to do a job that’s physically impossible. That’s why we’re striking for better conditions in these heatwaves.”

Arriva North London has said that it takes the welfare of its drivers seriously and is working closely with Transport for London to support both them and customers during hot weather.

The Public and Commercial Services (PCS) union is running a “heatwave” strike action ballot of more than 300 members working for the V&A museums in London until August 20.

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. 

Today Bakers, Food and Allied Workers’ Union national president Ian Hodson warned workers are “struggling to make it through these worrying heatwaves… I’m scared more people will get hurt.”

“Heatwaves are becoming more frequent and extreme, and still there are no plans in place to protect workers or vulnerable people, the UK is being driven into a national health and safety crisis in a bus with no air-con and the brakes cut,” he added.

Aslef is campaigning for the industry to improve train driver cab design to ensure drivers are working at safe and comfortable temperatures.

Today, its general secretary, Dave Calfe, warned that current laws covering workplace temperatures do not apply to cabs, adding: “It’s time to protect all workers, not just transport workers, and for all of our workplace conditions to be improved to a safe and healthy level.”

More than 1,000 trade union members and the public took part in a national Heat Strike earlier this year. Petitions for a maximum working temperature have topped 180,000 signatures.

A government spokesperson said: “We have no plans to introduce a mandatory maximum workplace temperature.

“The Health and Safety Executive has shared guidance for employers to plan for and support those working in extreme heat to keep workers healthy and safe.”