Flash flooding has caused travel chaos in parts of England as thunderstorms dumped almost half a month's rain in some parts within hours.
A train from Milton Keynes to Euston derailed in a landslip near Watford Junction, injuring two people.
The worst-hit areas are across the east, south and south-east of England, with disruption due to continue into the weekend.
Roads, homes and a hospital are flooded and lightning has damaged buildings.
The disruption includes:
- The derailment of the London Midland 06:19 BST service from Milton Keynes to Euston near Watford Junction
- London Midland has warned delays will run into the weekend with many services cancelled out of Euston until further notice
- The flooding of a maternity unit at Wallingford Hospital in Oxfordshire, with women going into labour to be sent elsewhere
- Paddington railway station power and signalling problems the causing delays and cancellations
- Reports of lightning striking houses in multiple locations including Bracknell, Caversham, and Bournemouth
- Waterlogged roads and rail stations, including Didcot Parkway and Newbury stations across Oxfordshire
- Major delays on the M25, M4 and M40 due to flooding
- Badly damaged homes after streets flooded
- Thousands of homes without power
Network Rail said CrossCountry, Great Western Railway and South West Trains were all affected with severe delays on dozens of services.
London Midland said the derailment had a knock-on effect on it trains, with hours of delays expected to last throughout the day and into the weekend.
Councils were working with emergency services to minimise disruption in areas of flash flooding, said Martin Tett at the Local Government Agency.
"The lack of warning and intensity of flash foods makes them very difficult to guard against," he said.
Thames Valley Fire Control said it had received "an enormous number of calls" since 18.00 BST on Thursday for Berkshire alone.
"There were a total of 174 calls which resulting in 158 incidents, 47 of which were flood related," a spokesman said.
'My mum panicked'
Mashood Shah, who lives at Walton Terrace in Woking, is one of hundreds of people across the country whose homes have flooded.
He described the moment water came pouring under his front door around midnight.
"My mum just said 'the water's all coming in' she was panicking. I had my wellington boots by the bed.
"I put them on and I came rushing down. I told my little brother 'stay up there, I will pass you everything'.
"The water came nearly to the top of my wellington boots."
Neighbour Beryl Baker said she had been flooded 11 times in the 66 years she had lived in her home.
The 84-year-old said there was faeces coming up through drains inside her bathroom.
"It's terrible, really terrible," she said. "I think it's awful that you've got to put up with this in this day and age. Especially at my age."
Met Office meteorologist Martin Combe said 32.8mm of rain had fallen in just three hours in Farnborough, Hampshire - nearly half the 70mm average for September.
The rain has been moving steadily east, and is expected to clear East Anglia by Friday evening.