Employers who fail to protect their workers from the effects of extreme heat could be breaking the law, the British trade union body the TUC has warned, as it has called for a legal maximum workplace temperature limit.
With temperatures continuing to soar across Europe and the U.S, the TUC reminded employers that, while under UK law there is no clear legal maximum workplace temperature, health and safety regulations placed a duty on them to make sure that the inside temperature was "reasonable" during working hours.
If the temperature got too hot then the regulations said employers must take action to reduce the heat by introducing air conditioning or distributing fans, providing plentiful amounts of cold drinking water, moving staff away from windows or allowing them to dress down.
The TUC has warned that if employers fail to keep workplaces cool, they could be liable if a member of staff falls ill because of the heat or has an accident at work because they are feeling tired or faint.
But the lack of a clear maximum temperature meant that many employers were confused about what they must do and when they have to act.
The union body has said it wants to see a maximum working temperature of 30ļC, or 27ļC for those doing strenuous work.
At this point employers would have to take steps to cool workplaces down, it argued.
Current UK health and safety law specifies a minimum workplace temperature but no upper limit.
TUC general secretary Brendan Barber said: "Whilst most sensible employers will be doing their utmost to keep their staff cool in the oppressive heat, there will always be some too mean to do anything to bring their office or shop temperatures down.
"Bosses who fail to adopt the cool work approach risk damaging their firms' productivity as their employees wilt in the heat.
"They also increase their chances of ending up in court, because someone has fallen ill or has had an accident because it got too hot.
"Employers clearly cannot control the weather, but there is much they can do to keep staff cool, and a clear maximum temperature would make a real difference," he concluded.
Forecasters have predicted that UK temperatures will cool in the coming days before rising again during the first half of August.