The Met Office has issued a yellow warning for thunderstorms across London after a few days of scorching temperatures.

The warning advises of the chances of “isolated flooding and disruption” for the South East between 12pm and 11.59pm on Wednesday.

It states that spray and sudden flooding could lead to difficult driving conditions and some road closures, with a “small chance” that some communities could be cut off by flooded roads.

It also warns of a “slight chance” of power cuts for homes and businesses.

The advisory adds: “There is a small chance that homes and businesses could be flooded quickly, with damage to some buildings from floodwater, lightning strikes, hail or strong winds.”

The UK Health Security Agency (UKHSA) has issued yellow heat health warnings for all areas of England, except the North East and North West, until Friday.

It warned that expected hot weather may have “significant impacts” on the health and social care sector across the South East and London, with minor effects elsewhere.

Here is the hour-by-hour forecast for today (Wednesday)

5am - Sunny intervals 19C

6am - Sunny intervals 19C

7am- Sunny intervals 19C

8am - Sunny intervals 20C

9am - Sunny intervals 22C

10am - Sunny intervals 23C

11am - Sunny intervals 24C

12pm - Sunny intervals 25C

1pm - Cloudy 25C

2pm - Cloudy 25C

3pm - Light shower 25C

4pm - Light shower 24C

5pm - Sunny intervals 24C

6pm - Sunny intervals 24C

7pm - Sunny intervals 23C

8pm - Sunny intervals 23C

9pm - Partly Cloudy 22C

10pm - Partly cloudy 21C

Here is the hour-by-hour for tomorrow (Thursday)

7am - Sunny intervals 19C

10am - Sunny intervals 22C

1pm - Heavy shower 26C

4pm - Light shower 27C

7pm - Sunny intervals 25C

10pm - Partly cloudy 22C

Forecast in full

Wednesday: Cloud will increase during the afternoon, turning the sunshine hazy at times. Feeling very hot in the sunny spells, but fresher along the east coast in a sea breeze. Maximum temperature 31 °C.

Outlook for Thursday to Saturday: Sunny spells and a risk of thunderstorms on Thursday. Dry and hot on Friday with increasing cloud. Fresher on Saturday after a spell of rain.

Met Office chief meteorologist Paul Gundersen said: “There is a chance of some thundery outbreaks for some in the South and East from later on Wednesday, which will be the first signs of the UK’s transition to a more unsettled regime, with warnings issued to highlight potential impacts.”