Another weather warning has been issued across south London as heavy thunderstorms are forecast to break up the heatwave this weekend.

The yellow warning, covering the south of England, will be in force from early on Saturday until midnight on Sunday.

Heavy thundery showers, similar to those that saw flooding across the region yesterday, are expected to break out over the course of the weekend, especially on Sunday, when these could be widespread and torrential in places.

Whilst rainfall totals will vary considerably from places to place, up to 100mm of rain could build up in some locations, with potential impacts including the chance of some flooding as well as poor travel conditions due to surface water.

Lightning and hail are expected to be additional hazards.

The warning comes as western areas of the UK continue to deal with an amber extreme heat warning that is currently in force, with temperatures regularly getting in to the high 20s and low 30s Celsius, which is due to expire in the south on Thursday night.

Met Office Deputy Chief Operational Meteorologist David Oliver said: “This yellow rain warning comes as temperatures are set to dip for many areas over the weekend.

"A spell of rain, heavy in places perhaps with some thunder, moves in from the southwest late on Friday and into Saturday.

“This is followed up by an unsettled weekend for much of England and Wales with showers breaking out widely. Some very heavy showers or thunderstorms are on the cards, especially during Sunday.

"However, farther north it is set to stay mainly dry with some fine weather, although it will not be as hot as has been seen recently.”

The unsettled conditions are set to continue for much of the UK into next week, with showers or longer spells of rain set to affect many areas, although still with some drier, sunnier spells.

The current extreme heat warning, the first issued by the Met Office, coincides with Public Health England’s Heat Health Alert through to Friday, reflecting the risks to the health sector in England.