As another spell of extreme heat builds over the country, the question lands on every office floor, kitchen and building site come Monday morning: can you refuse to work when it's too hot? The answer surprises most people. There is no legal maximum workplace temperature in the UK, none at all. But that does not mean employees are without rights, or employers without obligations.
No legal maximum, and yes, that is deliberate
The law sets a floor but no ceiling. The Workplace (Health, Safety and Welfare) Regulations 1992 require the temperature inside workplaces to be «reasonable», and the accompanying guidance suggests a minimum of 16°C, or 13°C for strenuous work. Going up the thermometer, nothing: no figure at which work must legally stop, however brutal the heatwave.
That gap is no accident: regulators argue a single number cannot fit both a foundry and an air-conditioned office. It has been contested for years, though. The TUC has long campaigned for a legal maximum of 30°C, or 27°C for strenuous jobs. Until that changes, «reasonable» is the standard, and it does more work than it seems.
What your employer must actually do
Under the Health and Safety at Work Act 1974, employers owe a duty of care to protect employees' health, and the HSE is explicit that heat is a workplace risk that must be assessed and managed like any other. In a heatwave that means concrete steps: relaxing dress codes, providing fans or ventilation, moving desks away from sun-struck windows, offering cool drinking water, shifting hours away from the afternoon peak, and easing physical workloads.
A significant share of staff struggling in the heat is precisely what the «reasonable temperature» rule is designed to catch: if thermal comfort collapses for many, the employer is expected to act, not to shrug.
Walking out: possible, but tightly framed
Here is the heart of it. Section 44 of the Employment Rights Act 1996 protects employees who leave, or refuse to return to, a workplace in the face of serious and imminent danger they reasonably believe they cannot avert. Dismissing or penalising someone for doing so is unlawful.
But heat alone does not automatically clear that bar. Everything is case by case: how hot, doing what, for how long, in what state of health, and with what precautions already in place. Heavy manual work in direct sun with no water or breaks is a world away from a warm but ventilated office. Walk out over the latter and you risk a disciplinary; stay silent in the former and you are bearing a risk the law never asked you to bear. The sensible sequence: raise it formally first, walk out only if danger is genuinely serious and imminent.
And if you work from home?
For home workers the duty of care does not vanish, but the thermometer becomes largely your problem, and cooling the home office is where the real money goes. A desk fan costs pennies a day at the current price cap, while a portable air conditioner can add pounds per day: our guide to portable air conditioner running costs puts numbers on it, and our heatwave survival guide covers the cheaper ways to keep a workspace bearable.
Worth remembering: there is no legal maximum temperature at work in the UK; employers must nonetheless assess and manage heat as a risk, from dress codes and water to ventilation and adjusted hours; leaving your post is protected only in the face of serious and imminent danger, judged case by case; and the TUC's proposed 30°C ceiling remains, for now, a campaign rather than a law.
What to do, practically, this week
If the heat is becoming hard to bear: put it in writing to your manager or health and safety rep, asking for specific measures: earlier hours, breaks, fans, relaxed dress. Involve your union rep or staff representative if you have one. Keep a note of temperatures if you can. And if conditions genuinely present a serious and imminent danger, Section 44 exists precisely for that moment. Extreme heat is not a quirk of the calendar: it is an occupational risk, and the law already treats it as one.