Thunderstorms are expected to sweep across the UK this weekend and it’s possible they could cause flash flooding, forecasters have warned.

Train and bus delays could also occur in parts of the UK and some communities might be cut off by flooding as warm, humid air causes storms to develop, the Met Office said.

On Sunday, some areas could see up to 30mm of rainfall in an hour.

A yellow thunderstorm warning has been issued by the Met Office across most of England and Wales for the whole day.

Thunderstorms could result in flash floods across the UK this weekend

Despite the expected rain, temperatures will continue to reach the high 20s.

It comes after NHS chiefs warned the hot weather had contributed to “one of the busiest days on record” in Accident and Emergency departments on Thursday.

Charity Asthma + Lung UK added that the humidity had caused an “unseasonal spike” in asthma-related A&E visits and warned that thunderstorms over the weekend could cause “life-threatening” asthma attacks.

In Kent and Sussex, hosepipe bans have been introduced due to “record levels” of demand for drinking water.

What different Met Office weather warnings mean

Met Office spokesperson, Grahame Madge, said: “There are risks of flash flooding associated with these forecast thunderstorms.

“Thunderstorms can unleash very intense rainfall and even hail.

“The impacts from this sudden release of precipitation can create local difficulties especially in urban areas as intense rainfall can lead flood waters to rise on roads, underpasses.

“This far out it isn’t possible to forecast exactly where these systems will form but we are confident that some will experience intense conditions.

“We advise the public to follow the forecast and warnings so they can be prepared should thunderstorms develop at short notice.”