UK weather: Temperature records could tumble before thunderstorms hit Britain

Highs of 37C forecast before heat gives way to cooler conditions for weekend

Britain could see its all-time record temperature broken as the summer heatwave continues.

Recorded in Faversham, Kent in August 2003, 38.5C still tops the temperature chart and while forecasters are predicting highs of 37C on Friday they said there is a chance the record could be beaten.

The record for the hottest July day, currently 36.7C recorded at Heathrow in 2015, is also in danger of being surpassed.

​Temperatures are expected to reach the mid-30s for much of east and south England, but could push higher if the sun stays out, forecasters said.

However, lightning, hail and possible flash flooding are set to hit eastern areas on Friday afternoon, with the Met Office issuing a thunderstorm warning that will remain in place until midnight.

“The reason there's some uncertainty is because of the thunderstorms, how many we see and where they get going, torrential rain, the risk of local flooding, large hailstones potentially damaging, lots of flashes of lighting and rumbles of thunder,” Met Office meteorologist Alex Deakin said.

“Roads like the M11, M18, M1 and A1 won't be very pleasant, a lot of spray and surface water around.”

Thursday saw the hottest day of the year so far, with temperatures reaching 35C at Heathrow.

A mix of toxic air, extreme highs, emissions from the continent and a lack of cloud cover also led to a “high” air pollution alert to be issued for London.

Meanwhile, authorities said the heatwave was putting extra strain on parts of the NHS, while many nursing unions said the high temperatures had left some of their members dizzy and exhausted.

Fire brigades also called for a ban on barbecues in parks and drivers were urged not to throw rubbish following a string of grassland fires in recent weeks.

Passengers on the Eurotunnel endured five-hour delays as air conditioning units failed, while commuters on London's Underground travelled in temperatures above the legal limit for transporting livestock.

Showers will sweep across parts of Wales, south west England and Northern Ireland on Friday evening, ushering in cooler temperatures over the weekend.

Most places will see temperatures closer to average for the time of year, around the high teens to low 20s, with rain and breezy conditions on the way.

Some areas will see a drop of more than 10C between Friday and Saturday.

“Weather fronts are trying to come in from the Atlantic and eventually they will do so,” Mr Deakin said. “And that has the impact of ousting the really hot and humid air. It turns runs cooler for the weekend, fresher, more comfortable at night.”

Scientists have warned that climate change is making such heat extremes more likely, and the report comes as northern Europe swelters in a prolonged heatwave.

Additional reporting by PA