A man has died as Storm Desmond tore through Britain, bringing strong winds and heavy rain which caused Cumbria to declare a major incident.
The Environment Agency made 130 flood warnings, while residents in some areas were evacuated from their homes and there were a number of road accidents involving heavy goods vehicles.
A 90-year-old man who lost his life is believed to have been blown into the side of a moving bus by a gust of wind, near Finchley Central Tube station, north London, a Scotland Yard spokesman said.
Rain continued to fall overnight in Scotland, northern England and northern parts of Wales, and is likely to continue for a few hours yet, forecasters said. Some areas have already seen more than a month's worth of rain over the last 24 hours.
The deluge left streets lined with terraced houses looking more like rivers as rescue teams set off in rubber dinghies to help stranded locals. Many remain underwater, while some have been left covered in mud and debris.
Cumbria was among the worst affected by the onslaught, with the village of Braithwaite becoming completely cut off when its main bridge, the Coledale High Bridge, collapsed as the river burst its banks.
In Carlisle, flood levels continued to rise and helicopters carried out rescue missions overnight as cars became almost entirely submerged. Military forces have been called in to help evacuate people who wish to move, including elderly people, pets and families with babies.
The British Red Cross teams set up rest centres in Keswick, Appleby and Kendal, while medical groups issued an urgent call to draft in extra doctors amid fears the storm could cause casualties.
Adrian Holme, from Cumbria Fire and Rescue Service, told the BBC the flood was "unprecedented" and "exceptionally challenging" as more than 100 people were evacuated from Keswick.
He said it was "absolutely devastating", adding: "The flood defences that were built here in 2012 haven't been breached, they have been over-topped. We have had 24 hours of constant rain."
Power supplies were also seriously affected and at least 55,000 homes in Lancaster, Morecambe, Carnforth will continue to face cuts for a number of days after flood defences protecting a major substation were breached overnight.
Electricity North West said another 4,000 properties were without power across Cumbria as flooding continued to cause further faults.
A fire and rescue crew had to save a member of the public who was found clinging to a tree after they tried to reach a horse stranded in a flooded field in Northumberland, while fire services in Lancashire responded to more than 300 calls for help, including road traffic collisions and two fires.
The cross-Tyne Shields ferry Spirit of the Tyne was rescued by Tynemouth RNLI lifeboat volunteers in a dramatic mission on Saturday night after the ferry's engine failed on its final crossing of the night from North to South Shields.
As the lifeboat was being launched the Port of Tyne pilot launch Collingwood managed to evacuate the small number of passengers from the ferry, leaving just the skipper who was desperately trying to get the ferry's engine restarted. No injuries were reported.
Looking ahead, MeteoGroup forecaster Gemma Plumb said weather should dry out later during Sunday - before more rain heads up from the south west on Sunday night.
Environment Secretary Elizabeth Truss said that an emergency Government meeting has been called to organise effective responses for the worst affected.
She said: "We know what a devastating impact flooding has on communities and our thoughts are with those affected this weekend.
"The Environment Agency, local authorities and the emergency services are already working around the clock to protect properties, help those already affected and reduce the risk to others and we are working with them to ensure they have everything they need to respond. I urge people to check the latest flood updates via the EA website and Twitter."