Can a driver refuse to take a lorry out with no air conditioning?

It's the question that lands in every transport office the moment the temperature climbs: the cab air con has packed up, the forecast says 34°C, and the driver doesn't want to take the vehicle out. Are they within their rights, or is it a disciplinary matter waiting to happen?

The honest answer is: not automatically — but in the right conditions, yes. And the grounds aren't the ones most people reach for first. This isn't a roadworthiness question. It's a health, safety and fitness-to-drive question, and understanding the difference keeps both driver and operator on solid ground.

Air conditioning is not a roadworthiness item

Let's clear the biggest myth out of the way. A broken air con does not make a lorry unroadworthy. It isn't checked at the annual test, it isn't a construction and use requirement, and it isn't a defect that prohibits the vehicle from being used. So a driver can't refuse on the basis that the vehicle is "not legal to drive" the way they could for a brake, tyre or light defect. On roadworthiness grounds alone, a dead air con doesn't stop the wheels turning.

That surprises people, because air con feels essential in a heatwave. But feeling essential and being a legal test item are two different things.

There's no legal maximum temperature either

The second myth is that there's a magic number — that once the cab hits some legal figure, the driver can down tools. There isn't. There is no maximum workplace temperature in UK law (HSE, no date; GOV.UK, no date). The often-quoted 16°C (or 13°C for strenuous work) is a minimum guideline for comfort, not a legal limit, and there's no upper equivalent (HSE, no date).

So a driver can't point at a thermometer and claim an automatic right to refuse. The law deliberately avoids a fixed number, because heat risk depends on humidity, ventilation, workload and the individual, not air temperature alone.

Where the real grounds are: fitness to drive and welfare

Here's where it turns. Two duties do genuine work in this situation.

The duty not to drive when unfit. A driver must not drive if their condition would make them a danger — and severe cab heat can do exactly that. A driver in a poorly ventilated cab with broken cooling, in temperatures pushing 40°C, faces a real risk of fatigue, dehydration, heat stress and loss of concentration. In a safety-critical role behind 40 tonnes, a driver who reasonably judges that the heat would impair safe control is not being difficult — they're meeting their responsibility. A driver who becomes unwell mid-shift and stops is on very firm ground.

The employer's health and safety duty. Even without a maximum temperature, an employer must ensure, so far as is reasonably practicable, the health, safety and welfare of employees (Health and Safety at Work etc. Act 1974, s.2), provide a reasonable working temperature (Workplace (Health, Safety and Welfare) Regulations 1992, reg. 7), and assess the risk (Management of Health and Safety at Work Regulations 1999). Heat is a hazard like any other, and it has to be managed (HSE, no date).

Alongside those, employment law protects a worker from being penalised or dismissed if, faced with circumstances of danger they reasonably believe to be serious and imminent, they refuse to work (Employment Rights Act 1996, ss.44 and 100). The bar is that "reasonable belief in serious and imminent danger." On a mild day with working windows and fans, a broken air con on its own won't clear it. In a genuine heatwave with the cab at 40°C-plus and a driver starting to feel the effects, it's a far stronger position.

Don't confuse lorries with buses

One trap worth avoiding. Buses are a special case and shouldn't be used as the yardstick. In London, all bus driver cabs must by policy be fitted with an air cooling or air conditioning system, and Transport for London's position is that a bus shouldn't be taken into service if it isn't working, with drivers told they won't be penalised for refusing. That's a TfL and operator rule for PSVs — the underlying legal duties are the same, but there's no equivalent "must be fitted and working" rule sitting over HGVs.

The right process (for driver and operator)

For a driver, the defensible route is straightforward: report it as a defect and a welfare concern through the proper channel, don't simply walk off; let the operator act; and if it's genuinely extreme, record date-stamped cab temperature readings. For an operator, the response is to risk-assess and remedy — repair the system, swap the vehicle, adjust the schedule to cooler hours, or provide breaks and water — and to document what was done. Crucially, an operator should never penalise a driver for raising a genuine welfare concern.

Where this sits in your compliance system

This is squarely a management-system issue, and on audit it falls under the driver health policy (framework section 9.4) and the health and safety and staff fatigue policy (section 9.7). A well-run operator has a hot-weather or thermal-comfort plan, a defect-reporting route that captures cab welfare and not just mechanical faults, and a culture that treats a heat refusal as a risk to be managed rather than an argument to be won. Get that right and the broken air con becomes a maintenance job, not a standoff.

It's also a moving target worth watching: the government has committed to modernising health and safety guidance on extreme temperatures, and the HSE is reviewing the relevant Approved Code of Practice (House of Commons Library, 2026). The direction of travel is towards clearer expectations, not away from them.

If you'd like your driver welfare, fatigue and health and safety policies reviewed as part of a full compliance audit, that's exactly what we do. Get in touch at enquiries@ukfleetaudit.co.uk.

This article is general guidance, not legal or employment advice; for a specific dispute, seek professional HR or legal input.

References

Employment Rights Act 1996, c. 18. Available at: https://www.legislation.gov.uk/ukpga/1996/18 (Accessed: 7 July 2026).

GOV.UK (no date) Workplace temperatures. Available at: https://www.gov.uk/workplace-temperatures (Accessed: 7 July 2026).

Health and Safety at Work etc. Act 1974, c. 37. Available at: https://www.legislation.gov.uk/ukpga/1974/37 (Accessed: 7 July 2026).

Health and Safety Executive (no date) Temperature in the workplace: what the law says. Available at: https://www.hse.gov.uk/temperature/employer/the-law.htm (Accessed: 7 July 2026).

Health and Safety Executive (no date) Thermal comfort. Available at: https://www.hse.gov.uk/temperature/thermal/ (Accessed: 7 July 2026).

House of Commons Library (2026) Working in hot weather: what does the law say? Available at: https://commonslibrary.parliament.uk/research-briefings/cbp-10925/ (Accessed: 7 July 2026).

The Management of Health and Safety at Work Regulations 1999, SI 1999/3242. Available at: https://www.legislation.gov.uk/uksi/1999/3242 (Accessed: 7 July 2026).

The Workplace (Health, Safety and Welfare) Regulations 1992, SI 1992/3004. Available at: https://www.legislation.gov.uk/uksi/1992/3004 (Accessed: 7 July 2026).