Flooding could hit the capital overnight as the glorious Bank Holiday sunshine makes way for thunderstorms.

The Environment Agency has issued a flood alert in south east London, with rain expected to hammer the capital on Sunday night.

Flooding could hit streets in Bromley, but it is not expected to reach homes or businesses, the Agency said.

It is thought that flooding, with almost 45mm of rainfall expected in just six hours, could occur if the banks of the Ravensbourne burst.

Chris Hazelton, duty manager at the Environment Agency, said: “We have issued pre-emptive flood alerts on our fastest responding catchments.

"This is based on the latest forecast we have received regarding the expected thunderstorms tonight and into tomorrow morning.

"This is currently as a precaution as the location and timing of potential heavy rainfall remains uncertain. We have staff monitoring the weather and we are prepared to react accordingly if necessary.”

A spokesman added: “Thunderstorms are expected this evening and overnight. The rainfall may be intense and very localised. We are issuing a flood alert based on the forecast rainfall.

“There is significant uncertainty about how much rain will fall and exactly where, however rainfall totals could be as high as 45mm of rain in a 6 hour period."

He added: “f we receive all of the predicted rain, there is a chance that the Ravensbourne may come out of bank, leading to flooding of nearby roads and low-lying land.”

The warning comes after temperatures hit 27 Celsius over the Bank Holiday weekend, with Londoners taking to parks across the capital to bask in the sunshine.

Thunderstorms are expected to arrive at 10pm on Sunday.