Trade unions have warned of intolerable working conditions for workers caused by extreme temperatures in Britain this summer, as some NHS hospitals report record numbers of people attending A&E because of the heat.

The TUC said action was needed to protect workers from health risks posed by the abnormally high temperatures, as the mercury hit 34.1C in Norfolk on Friday, after Thursday’s year-high of 35C, recorded at Heathrow, west London.

The weather has brought with it serious health concerns as higher temperatures put people suffering from cardiac, kidney and respiratory diseases at greater risk, with associated higher air pollution also posing a danger.

“With heatwaves becoming more common, we need clear and sensible rules to protect working people,” said the TUC general secretary, Frances O’Grady. “We’ve had legal minimum temperatures at work for a long time, which work very well. The government must now act quickly on the recommendation by MPs for maximum limits on how hot workplaces can get.”

The TUC is campaigning for a maximum legal temperature on indoor workplaces of 30C (or 27C for strenuous work), with employers forced to introduce cooling measures when the temperature hits 24C.

It says many offices are not air-conditioned or cooled and its safety representatives have also reported issues in manufacturing plants, catering establishments and warehouses. Low-paid workers are often most at risk, working in sweatshops that live up to their name, it said.

Jerry Swain, Unite’s national officer for construction, said people in the building industry were at particular risk from unscrupulous employers.

“There are concerns on two levels,” he said. “One is those people out in the sun all day and secondly those who work inside in confined areas where heat can build up if there is a lack of circulation of cool air.

“We’ve had reports where nothing is being done and people are just expected to carry on working. Heat can make you lightheaded or dizzy and on a construction site, where you’ve got machinery, that’s a real risk.”

He said staff must be allowed to take breaks and be provided with cold water.

As well as dealing with patients vomiting and fainting, hospital staff have also been affected by working long shifts in hot conditions.

Unison has said hospital management should deploy mobile air conditioning units and make sure fans and cool drinking water is made available. Staff must also be allowed to take regular breaks, the union said.

The rise in the number of people attending A&E includes large numbers of people from care homes, according to NHS Providers, which represents trusts.

Caroline Abrahams, the charity director at Age UK said: “The hot weather can be really challenging for many older people because as we age, our bodies become less able to cope with extreme temperatures, increasing susceptibility to heat-related illness.

“Some older people also struggle to drink enough in normal temperatures, so when it is exceptionally hot care homes need enough staff who in turn have enough time to help all their residents keep up their fluid intakes.”

Figures published by the Environment Agency on Friday showed that between 1 and 24 July the east of England experienced only 4% of its long-term rainfall average for the month.

An average of 2mm of rain fell during that period and there has been only 11mm since the start of June. For England as a whole, rainfall has been 15% of the long-term average since the start of July.

Although thunderstorms offered some relief from the heat in parts of the UK on Friday, they also brought with them their own problems. At one point, Northern train services said all its lines were blocked as a result of lightning damaging the signalling system between Leeds and York.

