Yellow thunderstorm warnings have been issued by the Met Office with torrential rain bringing around 20-30mm (about an inch) in an hour but as much as 60-90mm of rain in a few hours. This is well over a month's worth of rain falling in a few hours for the biggest storms.

An amber warning covers a large swathe of southeast England, including Greater London, from 4am until 11am on Saturday, with concerns about flash flooding, travel disruption and possibly power cuts. Yellow warnings for heavy rain and thunderstorms cover much of Scotland and England on Saturday, as the wet weather spreads northwards.

The Met Office has issued a yellow weather warning for heavy rain and isolated thunderstorms for Cornwall this weekend. Heavy rain is expected to fall from 12 noon on Sunday, July 20 to 3am on Monday,