UK storm alert: Met Office issues urgent nine hour thunderstorm warning as chaos expected

Thunderstorms are expected to wreak havoc on parts of the UK tonight, as the Met Office warns of an imminent risk of flash flooding.

The forecaster has placed 23 local authority areas in and around London, the south east and the Midlands under a yellow weather warning which has already come into force.

It will last until the early hours of tomorrow, with its expiry date set to 2am. Among the chaos expected, it urges people to be vigilant as there is a risk of lethal hail, damage to buildings and power cuts.

In its statement issued this evening, the forecaster added that thunderstorms have already started in some areas and that they are expected to become more widespread as dusk sets in.

It says: “Thunderstorms with frequent lightning have already affected parts of the warning area, these continuing into the evening in places.

“An increasing risk of longer-lasting intense downpours too, especially later this evening and further east across the warning area, for example towards south Lincolnshire and East Anglia.

“These storms are likely to be focused in relatively narrow bands, so some places will miss the worst, while a few locations might catch 25-50 mm of rain within two or three hours, along with frequent lightning and gusty winds.”

The warning also delivers the possibility of commuter chaos this evening, as flash flooding could lead to standing water on roads – and could halt rail services.

It says some buildings run a risk of being struck by lightning.