Can you refuse to work or send your kids to school during a heatwave?

There's no law in the UK that says a given temperature is too hot or too cold to work.

But guidance from the Health and Safety Executive (HSE) says employers must stick to health and safety at work law, which includes keeping temperatures at a "comfortable" level, and "providing clean and fresh air".

Workplace advice group Acas says that "except in extreme circumstances, workers usually need to follow their contracts and work with their employer to find a suitable and safe way to work".

Acas chief executive Niall Mackenzie says it is usually "a last resort in extreme circumstances" if a workplace has to be closed, or a worker is unable to travel or work because of the heat.

"Any such decision should only be taken where there are no alternative options and should be communicated clearly and in good time," he says, adding employers should be flexible and consider relaxing rules where possible.

Last month, the Climate Change Committee (CCC) said the UK should introduce a maximum temperature for workplaces to protect people as heatwaves intensify due to climate change.

In cold weather, the HSE says the minimum temperature for an indoor workplace should normally be at least 16C - or 13C if the work involves "rigorous physical effort".

The HSE says employers should let staff work flexibly where possible and move workers to cooler parts of the building.

Relaxing formal dress codes and allowing enough breaks to allow workers to get cold drinks or cool down can also help.

Employers can provide fans or air conditioning and, where possible, windows should be opened to keep air circulating.

If you are working from home, close curtains to block out the sun. In the morning and evening, open windows on opposite sides of your home to let hot air out and cold air in. Use a fan to encourage airflow.

For those working outside, the weather can have a "serious impact" on health, the HSE says, if the risks have not been properly managed.

The HSE suggests that work should be rescheduled to cooler times of the day, and that employers introduce more frequent rest breaks, introduce shading to rest areas and provide free access to cool drinking water.

It also says workers should be encouraged to remove personal protective equipment when resting to help them cool down.

Acas says staff working outside should wear appropriate clothes and use sunscreen to help protect them from sunburn.

The heatwave could lead to transport services being disrupted. Hot weather can affect overhead power lines on the railways and also cause rails to buckle.

Acas notes that if public transport is affected, it could impact staff attendance and their ability to get into work on time.

It says people should check timetables in advance, and employers should be flexible.

National Highways says drivers should take plenty of drinking water on journeys, including enough for passengers.

If possible, it also advises changing travel times to avoid the hottest days and times of day.

Motoring group the RAC has said drivers whose cars don't have effective air conditioning should "strongly consider" postponing non-essential journeys until the weather warnings are lifted.