THUNDER storms and heavy rain are forecast for Wirral today to mark the end of a three-week heatwave which has seen the hottest temperatures in seven years, weather experts have said.

Thunder and lightning began overnight and will last intermittently throughout today.

The sharp change in weather comes after weeks of scorching temperatures, which yesterday peaked at 33.5C in London - the hottest day since July 20, 2006.

The storms will thunder over the Midlands as well as eastern, central, northern and southern parts of England, with the East Midlands, London and Kent seeing the worst of the weather.

Temperatures will dip to the high 20s and remain very humid in the South East, but the west of England, Wales and Northern Ireland will be far cooler before the rest of the country gradually follows.

Forecaster Brendan Jones of MeteoGroup, the weather division of the Press Association, said: "In the last few weeks an area of high pressure has hung over the UK creating settled, very hot conditions.

"But now air is pushing in from the Atlantic and meeting this humid air, and the combination is causing these strong and violent storms that will last on and off throughout the day and linger into Wednesday.

"The main threat is of flash flooding from localised but torrential rain, especially as the ground is so dry and solid it will not soak up the water very easily.

"Another threat is from the frequency of the lightning bolts, which could come down to the ground and cause damage. It will remain quite hot and humid in some areas today, but generally everywhere will now start to cool off."

The overall trend for the rest of the week will see the UK gradually cool down, with a continuing risk of showers and thunderstorms.

By next week the temperatures are expected to settle in the low 20s.

View the Globe's seven-day forecast here http://www.wirralglobe.co.uk/li/weather.in.Wirral/