Workers might quickly be allowed to stroll out of their workplace if it is too sizzling

Ministers are facing pressure to introduce a maximum workplace temperature, over which workers will be legally allowed to walk out

Staff could soon be legally allowed to walk out of sweltering offices as ministers come under growing pressure to bring in a maximum workplace temperature.

Campaigners and unions are demanding a lawful limit to protect boiling folk from grafting in sweatboxes after three brutal heatwaves so far this summer.

Current rules set a minimum workplace temperature but there is no maximum, leaving millions to suffer through scorching shifts even when thermometers climb above 30C.

Some workplaces hit more than 40C.

The push comes after the UK’s June heatwave was linked to an estimated 440 deaths a day during its three-day peak.

Schools were forced to shut, hospitals struggled with overheating equipment and transport networks buckled under the blazing conditions.

Trade unions want a legal indoor limit of 30C, or 27C for physically demanding jobs, arguing staff should not have to risk their health simply by turning up for work.

The Climate Change Committee, which advises the Government, has already urged ministers to introduce maximum workplace temperatures to improve safety as Britain faces hotter summers.

Pressure has also been mounting in Parliament, with Green MP Hannah Spencer planning to introduce a Bill aimed at paving the way for a legal heat cap.

London Mayor Sadiq Khan has backed the idea, warning extreme heat is becoming “a growing reality”.

Teachers described children lying on classroom floors with wet towels to keep cool and doctors have warned of MRI scanners, radiotherapy machines and hospital cooling systems failing during recent heatwaves.

The Government has said it has “no plans to introduce a mandatory maximum workplace temperature”.

But ministers said the Health and Safety Executive will launch a public consultation on workplace health and safety later this year.