One person has been taken to hospital and more than 200 people have been evacuated after the River Arun burst its banks in the wake of Storm Kathleen and the French-named Storm Pierrick.

A resident of Shoreham-by-Sea in West Sussex said flooding in the town was "scary and unprecedented", after he stayed awake until the early hours putting flood defences around his property.

Gareth Theobald, 36, said: "I was out the front of the building and watching the water just get higher and higher and higher, and then helping or stopping traffic going into the floodwaters and then just watching in disbelief as the whole of Brighton Road and our multimillion-pound development was being engulfed by floodwaters."

The industrial relations officer added: "The amount of water is scary and unprecedented and those houses opposite our development are lower-ground flats and they were all flooded under a foot or so of water."

He said he saw cars "driving into the floods at speed as well and getting stuck" and that "residents in the streets (were) trying to do what they can".

One local businessman in Littlehampton told Sky News his workshop had been inundated with around 1ft of water.

"I haven't even started to add the cost up," said Rob James, whose business makes machine parts.

"Once before it's flooded, but not on this scale.

"Probably last time I had two or three inches of water through the workshop. But this time it was bad, it was extremely high tide, extremely bad weather conditions, and no warning, basically."

A local resident said he had never seen anything like the level of flooding in the area before.

"We've had scares in the past but nothing ever like this," the man, who said he had been living in the area for 15 to 20 years, told Sky News.

"It was about midnight and the water started to come up, then all of a sudden there was a deluge. It just came through our doors. It was a frightening experience to see it in your front living room."

"We're coming back to assess the damage. It's completely wrecked, up to about 1ft off the ground. I do believe, talking to older people, this kind of thing hasn't happened for around 50 years. Hopefully it won't happen for another 50 years."

Ryan, who has lived in the area for around five years, said he woke up to find water "pouring through the door".

"We didn't get a warning," he said. "No warning whatsoever. Not even a text message."

He said repairs to his flat were likely to cost thousands of pounds. "Everything's got to go, everything. Everything you see on the ground level is going."

'Get to higher ground - we are expecting water to rise'

West Sussex Fire and Rescue Service said they had seen "severe flooding" across West Sussex, in areas like Earnley, Littlehampton and Bracklesham.

They added: "We are expecting the water levels to increase this afternoon. If you are directly affected, please get to higher ground if possible."

Around midnight, fire and rescue crews responded to flooding in Littlehampton - where 15 people were evacuated.

They were also dealing with a "severe flooding incident" at Medmerry holiday park between Bracklesham and Selsey, after being first called out at around 1am.

They urged anyone in the vicinity of the holiday park to get to high ground if they can leave their homes.

One resident shot a video of the water surrounding his chalet, saying "everything's underwater" and describing the area as "totally flooded".

Paul Maskell, a resident at Medmerry park, added: "I am adrift like Robinson Crusoe. It's incredible... totally flooded out."

At least 180 people have been evacuated from the holiday park and around 15 from Ferry Road and Rope Walk in Littlehampton, with one person showing signs of hypothermia, according to the fire service.

They were taken to hospital and South East Coast Ambulance crews assessed a number of other people.

Then shortly before 7am, crews attended flooding at Bracklesham Caravan and Boat Club and evacuated around 20 people.

West Sussex County Council warned that flooding could worsen throughout the day and the Environment Agency advised people to stay away from "coastal paths, piers and promenades".

The local council said: "It is also possible that the flooding may increase throughout the day. People directly affected should get to high ground if possible, unless unable to leave their residence. Otherwise, please avoid the areas to allow rescue operations to continue safely and effectively."

The Environment Agency has said there is a low risk of coastal flooding in the area today, adding it's likely that high tides or large waves will flood low-lying land and roads.

Weather warnings covering much of country

It comes as heavy rain and strong winds continue to batter parts of southern England, western Wales, Northern Ireland and Scotland over the next few days, forecasters have said.

Several services run by South Western Railway and Great Western Railway have been cancelled or delayed this morning due to flooding.

The Met Office issued six separate yellow weather warnings spanning Monday to Wednesday morning.

Winds in the southwest of England, including Cornwall and parts of Devon, could reach speeds of up to 65mph along some stretches of the coast.

The forecaster warned the strong gusts had a "small chance" of causing power cuts and damaging buildings.

A yellow weather warning for England's southern coast, including Southampton and Brighton, says winds are expected to reach 55mph, peaking at 65mph in some areas before easing off.

Get your local forecast from Sky News

Another yellow weather warning for Wales' west coast has been issued between 1am and 3pm on Tuesday, when "a spell of strong winds" will affect the region, with gusts reaching up to 65mph overnight.

In Scotland, up to 40mm of rainfall is expected in some areas between 1am and 6pm on Tuesday, while a few could see as much as 60mm.

Affected areas include Edinburgh, Glasgow, Perth and Aberdeen.

Further rainfall is forecast in western Scotland between 9am and 6pm on Wednesday and may cause flooding, with 15 to 25mm of rain expected to fall in most places and 40 to 50mm forecast on high ground.

The weather service warned rain and wind could disrupt rail and road travel across the country, as driving conditions worsen because of slippery road surfaces and limited visibility.

A low-pressure system, bringing the wet and windy weather, has swept in hot on the heels of Storm Kathleen.

Southern parts of the UK are being affected by Storm Pierrick, named by the French meteorological agency.

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Met Office forecast

Met Office forecaster Simon Partridge said that while these levels of rainfall would not be a "huge cause for concern" on their own, they will fall on "already saturated ground" which increases the risk of flooding.

"We'll continue with very unsettled weather as we head into spring, which is usually when we start to see things settle down a little bit more," he added.

"We're continuing with one area of low pressure after another, which is mainly down to the fact that the jet stream is a bit further south than it would normally be at this time of year."

The second half of the week should be a "bit drier" with warm temperatures in the south of the UK, before returning to normal over the weekend, Mr Partridge said.

He said: "It's actually quite warm conditions for the time of year - we could see 19C or 20C across eastern and southeastern parts of the UK come Thursday and Friday.

"But the north will always stay quite unsettled."