Doctors are demanding the right to go on ‘heat strike’ as temperatures are set to soar to 33C over the next few days.

Members of the British Medical Association (BMA) are calling on the union to demand that the NHS adopts a ‘national maximum workplace temperature’.

They said it should support staff to take ‘heat strike action’ if the temperature rises above this threshold, allowing all non-essential staff to walk out.

The limit should be set using available evidence, it added.

Some estimates suggest that staff concentration is affected from 24C, while the NHS says vulnerable patients could suffer at 26C.

The proposals, which also call for funding to keep NHS buildings cool enough to work, have been put forward by the BMA’s London regional council to be voted on at its annual meeting next week.

It said there is ‘evidence linking workplace heat to stress, poor health outcomes, reduced performance and decreased patient safety’ and that the ‘escalating climate and health emergency is increasing the frequency and severity of heatwaves in the UK, such that extreme working temperatures are very likely to become ever more common’.

The BMA today launched an indicative ballot of consultants, asking if they would be prepared to strike over pay.

The senior doctors, who earn an average of £145,000 a year, were awarded a pay rise of 4 per cent in May but had been seeking over three-times this amount.

A legally-binding ballot of resident doctors – previously known as junior doctors – is already underway. They say this year’s rise of 5.4 per cent should be closer to 30 per cent.

Yellow heat health alerts have been issued across England , with the UK Health Security Agency warning that the weather could have an impact on people’s health and put pressure on services.

Wards or clinical areas exceeded 26C on more than 6,800 occasions in 2022/23, according to NHS data.

The NHS warns temperatures this high put vulnerable patients at risk because they ‘are physiologically unable to cool themselves efficiently’.

This was up by almost a quarter on the year before, and more than double the 2,980 incidents that occurred in 2016/17.

Overheating in hospitals has previously caused issues with refrigerators used to store medicines and led to IT systems containing patient data to crash.

Matthew Taylor, the chief executive of the NHS Confederation, which represents health organisations, said: ‘We know that during heatwaves issues with inadequate ventilation can cause challenges with dealing with extreme heat.

‘This could have a detrimental impact on staff and patient wellbeing and hinder productivity unless organisations have the funding and capacity to fix faulty ventilation systems.’

A report produced by Round Our Way, a campaign group, stated: ‘In addition to patient distress, high temperatures also pose an occupational health risk to NHS staff.’

It cited evidence that the ‘cognitive performance’ of doctors and nurses decreased at high, or even mild temperatures of 24C, lowering their productivity.

Experts have also found that as many as nine in 10 hospital wards are at risk of overheating because of the design of buildings.

With a third of the NHS estate built before 1965 – more than 50 years before the recording of overheating incidents began – the buildings are primarily designed to keep heat in.