The Met Office has issued severe weather warnings as south London and Surrey looks set to be drenched by rain over the next two days

Forecasters predict that between 20mm and 50mm of rain - the average for the whole of August - may fall during Thursday and Friday. 

Torrential rain, lightning and hail are expected in London, as well as many other areas of the UK.

The Met Office also warned of a "significant risk of localised disruption due to surface water flooding" in London and the south-east.

A spokeswoman said: "Over the next 24 hours we expect heavy rain and thunderstorms to increase in this area. This is due to increasingly warm air being drawn into the developing low pressure system.

"This area of more widespread heavy, thundery rain is then expected to move northwards crossing the English Channel and into southern parts of England during the early hours of Thursday.

"These areas of heavy, thundery rain are expected to continue to spread northwards, affecting much of England and Wales at times through Thursday and into Friday. The rain may be torrential at times and there is also a risk of hail.

"In this type of situation, whilst we can be confident that many will see some heavy rain, details of where thunder, lightning and the highest rainfall totals - and therefore the highest risk of disruption - is rather uncertain."