The UK's heatwave has been washed out by thunderstorms on 16 September, bringing hail and lightning, as well as flash flooding and major travel disruption. The Met Office has been forced to issue a rare amber warning for the south-east of England, warning commuters to "be prepared" for severe weather conditions.

"An area of torrential thundery rain is expected to develop during early Friday morning, bringing the potential for exceptionally large amounts of rain within a few hours," a chief forecaster for the Met Office said. "Please be prepared for the potential for very severe weather conditions bringing flash flooding and disruption to transport."

As much as 100mm of rain is expected to fall in just 3-4 hours, bringing the likelihood of flooding of properties and businesses. In Watford Junction, two people were injured after a train derailed in a flood landslide caused by heavy rain.

Many have taken to Twitter to post images of flash flooding which caused travel chaos for commuters across the country during Friday's morning rush hour. Images and videos showed several train stations waterlogged, while one video appeared to show smoke billowing from a building in Newbury after a lightning strike.

UK weather
Flooding on Maidenhead High Street Dan Monroe/ PA

The Met Office's amber warning for rain warns about "exceptionally heavy, thundery rain" in eastern and southern regions of England. Meanwhile, a lower level yellow warning for rain is also in place in Wales and the rest of England.

The hashtag "thunderstorms" was trending across the country on Twitter as many took to social media to post images and videos from their areas. One woman even posted an image of a frog that had snuck into her kitchen to seek shelter from the stormy weather.

Shops about to be flooded out again #flood #ruislip #ruislipmanor #london

A video posted by Matthew Saward (@mattys86) on