The Met Office has forecast that the mercury will reach highs of 33C on Monday (July 11) in some parts of the UK, with hot temperatures forecast for the rest of the week.

Yorkshire is expected to see temperatures of up to 30C on Monday.

But how high does the temperature need to go before it becomes too hot to work?

This is what the TUC has said about working in hot conditions

During working hours the temperature in all indoor workplaces must be reasonable, but there’s no law for minimum or maximum working temperatures.

However, guidance suggests a minimum of 16ºC or 13ºC if employees are doing physical work.

There’s no guidance for a maximum temperature limit.

However, employers must stick to health and safety at work law, including:

keeping the temperature at a comfortable level
providing clean and fresh air

Employees should talk to their employer if the workplace temperature isn’t comfortable.

The Heath and Safety Executive has previously issued a number of guidelines when it comes to working environment.

They have said that, during working hours, the temperature in all indoor workplaces must be reasonable.

However, there is no maximum temperature given due to high temperatures of working in some places, for example a glass works or foundry.

While 'reasonable' is rather ambiguous, the law does say that an employer must act if a 'significant number of employees are complaining about thermal discomfort'.

If this is the case then your employer should carry out a risk assessment. There are six basic factors an employee should look at including air temperature, radiant temperature (ie, the temperature radiating from warm objects), air velocity, humidity, and what clothing or insulation workers are expected to wear.

A HSE spokesperson said: "As an employer you should be aware of these risks and make sure the underlying reasons for these unsafe behaviours are understood and actively discouraged and/or prevented. "The more physical work we do, the more heat we produce.

The more heat we produce, the more heat needs to be lost so we don’t overheat. The impact of metabolic rate on thermal comfort is critical."

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