Homes, roads and London underground stations were flooded over the weekend as thunderstorms battered the south of England.
A major incident is continuing in at least one of the capital's hospitals, with an evacuation of inpatients underway and incoming patients diverted elsewhere.
The Environment Agency has six flood warnings in place across the country’s south east, while there are 19 alerts for potential flooding active throughout England and Wales.
The wettest part of the country on Sunday was St James’s Park in London, where 41.6mm of rain fell.
A a major incident at Whipps Cross hospital in east London is continuing on Monday morning.
ITV News understands an entire block is without power without a timeline for resolution.
Around 100 inpatients are being evacuated to neighbouring hospitals, with ambulances redirected to St Barts, Royal London and Homerton - while elective surgery and outpatient appointments have been cancelled.
Both Whipps Cross and Newham Hospitals both urged patients to find alternative treatment centres after they were affected by the downpours.
Whipps Cross Hospital said it was “experiencing operational issues” and asked patients to use an alternative A&E “if possible”.
Newham Hospital had a similar appeal, writing on its Twitter account: “Our Emergency Department has flooded in some areas. We’re still here if you need us but to help us while we fix things please attend a neighbouring hospital if possible.”
On Monday, it tweeted that the Emergency Department "is now back up and running as normal".
Meanwhile, residents in north-east London used buckets, brooms and wooden boards to create makeshift flood defences for their homes, while water gushing from an Underground station was caught on video.
Londoner Eddie Elliott, 28, said the flooding was the worst he had ever seen, after he cycled past Queenstown Road station where the road had been “totally shut down”.
He said: “Having been born and raised in London, I have never seen anything quite like it.
“It stands out as the worst I’ve experienced personally … totally shut down the whole road with buses stood broken down in the water.”
In Suffolk, police were called to the town of Haverhill to help divert traffic away from the worst affected areas.
The fire service was also called out to multiple homes and businesses that were affected by the flooding.
Standon Calling festival in Hertfordshire was also cancelled due to the floods.
The festival said in a statement: “Unfortunately due to flooding we will no longer be able to proceed with the festival.
“If you can safely leave the site this evening please do so as soon as possible. We are working on getting everyone off site as safely and quickly as possible.”
The Met Office had a yellow warning for storms from Norwich to Plymouth in place until midnight on Sunday.
The rain brought an end to the heatwave earlier this week, but temperatures are set to rise in most places again on Monday as the storms clear, with the mercury predicted to reach 26C in London, 25C in Edinburgh, 24C in Cardiff, and 22C in Belfast.
The Met Office has predicted early cloud in some northern and eastern parts which will move up to Scotland, and sunny spells and scattered showers in most places throughout the day on Monday.