- Environment Agency has urged people to stay away from the sea and rivers because they risk being killed
- Teenager Harry Martin has gone missing after taking photographs of storm from cliffs close to Plymouth in Devon
- 21 severe flood warnings - the highest level - issued in South and West with 500 alerts in total across the UK
- Storm surge began at around 6am this morning - with risk of floods for 4 hours after high tide peaks
- But worse may be to come later with even stronger winds and waves predicted for this evening's high tide
- Streets and homes in Cornwall, Devon, Gloucestershire are already badly flooded after morning's deluge
- Police forced to spend time moving on weather watchers after large crowds gathered along the British coastline
- Motorist died when his car left a Cornish road as storm hit region with torrential rain and hail
- Met Office expects 70mph-plus winds and torrential rain to batter UK from today into next week, peaking on Monday
Surrounded: Cumbria resident Jane Davies watches helplessly from behind floodgates as the water reaches her home in the coastal village of Sandside on a day where much of Britain has been hit by a huge tidal surge
Pounding: Huge waves crash against the promenade wall in Porthcawl, south Wales, with the water and spray flying way above the buildings and lighthouse
Ripped up: The road in Amroth, West Wales has disintegrated because of the force of the sea today driven by high tides and strong winds
Massive tidal surges and 30ft waves have battered the south and west coastlines of Britain today, flooding huge areas, smashing roads and causing transport chaos.
But worse is to come tonight because more torrential rain, gale-force winds and another extremely high tide is forecast.
It came as hopes were fading for 18-year-old Harry Martin, who went missing on cliffs near Plymouth, Devon, after he told friends he was going to take photographs of the Atlantic storm.
The area is now being combed by a helicopter, the coastguard and members of the missing teenager's family, who last saw him yesterday.
Picture of Britain: After more than a month of terrible weather, large swathes of the country face serious flood threats with the majority in central and western England today
There are currently 21 severe flood warnings in place - the highest level - because the Environment Agency says there is a threat to life and property, with people being warned to stay away from the coast.
Police have been forced from emergency calls to move sightseers who decided to get close to the violent storm surge, putting them at risk of being hit by debris or washed away.
Areas are already under water but South Wales and North Devon are set to be worst hit tonight with 10.4m high tides hitting Porthcawl and 9.7m hitting Ilfracombe at around 7.30pm.
And as the low pressure hits Britain tonight wave forecasters have warned 40 to 50ft swells could hit Ireland and the south-west of England and Wales - this combined with the high tides could be disastrous for coastal towns and villages.
The high tides, or spring tides as they are known, are not unusual but the high waters combined with the massive storm swells mean coastal Britain is struggling to weather the storm.
Under water: The small town of Salcombe in south Devon was under water this morning as the high tide breached the sea defences there and flooded its narrow streets
Ed Temperley, editor of wave and surf forecasting website MagicSeaweed.com, said: 'These high spring tides will occur twice a day in the South West with the morning tide being slightly larger than the evening.
'The tidal range is by annual standards no means unusual. It is the combination of wind and swell effectively layering water atop the the full tide - commonly known as a storm surge - which is causing many of these flooding issues in coastal areas.
'We are expecting a second significant system, currently forecasting even larger swell for Monday next week, in excess of 50ft'.
Waves of 30ft have been consistently hitting the coast since the pre-Christmas storms. The waves are pushed in from the South Atlantic and crash straight into the West Country off the Atlantic Ocean.
The atrocious weather follows four drownings, widespread power cuts and severe flooding that wrecked Christmas for tens of thousands of families and the Government's COBRA committee - only held at times of national emergency - will meet this morning to discuss how to react.
Residents of low-lying areas have been warned to pack their bags because the violent Atlantic storm is expected to overwhelm large parts of the nation's battered flood defences, with similar sized tides also expected this evening.
Homes in Newport, South Wales, were evacuated this morning as the region faces its highest tide for 17 years.
High waves hit Penzance at just before 6am, and spread along the coasts of southern England, Wales and the north-west, reaching there at just after midday.
A motorist died today when his car left the A30 road at Two Bridges, Launceston, Cornwall, at around 8.10am as torrential rain and hail storms swept the region.
Police confirmed the male driver was killed in the crash when his car struck trees after careering off the dual carriageway.
Environment Secretary Owen Paterson sounded the alarm and said: 'The Environment Agency and local authorities have teams on the ground monitoring the situation as it emerges.
'Due to the continuing extreme weather, I will be chairing another Cobra meeting today to ensure that everything that can be done to help affected areas is being done.
'With a number of severe flood warnings still in place I urge everyone to follow the advice from the Environment Agency and police and to take every precaution.'
And Prime Minister David Cameron said last night: 'We are looking to have a combination of exceptional rain, wind and a surge in sea and high tides and so there are nearly 50 warnings put out around the whole of the west coast and south coast.
'We had a range of ministers from right across government attending the meeting, who will be working very closely with local councils, power companies, utility and transport companies, making sure that all of those organisations are absolutely prepared for the bad weather that is coming.'
Areas especially at risk include the Devon and Cornwall coastline, Dorset, the Welsh coast and the Isles of Scilly, the Environment Agency said.
The Environment Agency has issued 21 severe flood warnings for the Midlands and western areas, warning residents of danger to life. Some 437 less severe alerts were issued for other parts of the country as forecasters warned of winds of up to 60mph and days of rain.
Natural Resources Wales, the Welsh counterpart of the Environment Agency, said the tidal surge would be the highest to hit the coast since 1997.
An area of low pressure is expected to 'suck' up and raise the surface of the sea, which will then be blown by strong winds into the coastline.
The Thames Barrier was closed to protect London and police forces were poised to evacuate hundreds of homes.
In Scotland forecasters have warned of potential coastal flooding as more rain and high winds are set to hit the country. Heavy rain and gusts of up to 60mph could sweep across the country today, bringing further disruption after days of wet weather.
High tides and a storm surge have increased the risk of flooding in the Firth of Clyde, according to the Scottish Environment Protection Agency (Sepa).
A tidal surge is expected around lunchtime, particularly around the Firth of Clyde, Solway Firth and Ayrshire, the Scottish Government said.
Sepa has issued a flood alert for west central Scotland, warning that high water during early afternoon will be 'exceptionally high' with large waves likely.
It has also issued eight flood alerts and 17 flood warnings for other parts of Scotland.
The Met Office has issued yellow 'be aware' warnings of heavy rains and strong winds for the Highlands and Western Isles, Strathclyde, Central, Tayside, Fife, south west Scotland and Lothian and Borders.
And in Northern Ireland, residents of East Belfast were told to pack their bags in anticipation of evacuations as high water and heavy rain is predicted for midday today, Saturday and Sunday.
Police in Cumbria said flooding due to high winds and tides was causing problems across the county by lunchtime with cars getting stuck and sightseers putting themselves at risk by heading to the coast to witness the storm despite warnings.
Police said some motorists were also still trying to use flooded roads, causing additional problems for the emergency services. There were also reports of people crossing the live railway at Grange because the underpass was flooded.
Reckless sightseers and parents were slammed today for dicing with death in the huge waves which crashed over sea walls and piers.
Children as young as three or four were seen being drenched by waves despite a plea by the authorities to stay away from coastlines.
In one shocking sequence, a father holding his pre-school daughter in his arms is swept off his feet by a 20ft wave in Mullion Cove Harbour, Cornwall.
Onlooker Phil Rodda, 56, described how the man dropped his daughter as he was overcome by the torrent and his family were lucky to escape alive.
The retired civil servant said: 'We went down to see how rough the sea was - but from a safe distance away.
'We could see the young family, a man and a woman with three or four kids in all. The man was lifting his little girl up against the railings so she could get a better view.
'Suddenly this huge wave came crashing over the harbour wall and knocked the dad off his feet. He fell back onto the ground, still clutching the girl - they were very close to being swept away.
'The mother then ran over and grabbed the girl before they traipsed off looking drenched and rather sheepish.
'Anyone who knows the sea around here knows what it's capable off so I'm guessing they were from out of town.
'It was a ludicrous thing to do and incredibly dangerous.'
Shockingly, it happened in the same harbour where a couple were swept to their deaths by a wave during a seaside stroll in March 2007.
Patricia Evans, 43, and Stephen Tickell, 42, of Slough, Berkshire, died on the first day of their holiday as similar storms battered the area.
Yesterday many other sightseers across the south west were photographed losing their footing as they walked along promenades and sea walls.
Crowds lined Clevedon, Somerset, with others gathered at Newquay and Falmouth, in Cornwall, and Porthcawl, South Wales, to watch towering waves crash over the shore.
Around 40 people arrived in Clevedon and two boys aged no older than 10 were seen playing in the waves which smashed onto the seafront.
Police and North Somerset Council contractors closed off The Beach road to traffic in both directions as a safety precaution during the high tide.
It is estimated the tidal surge caused sea levels along the north Somerset coast to rise by massive 13.8m, causing spray to crash over the railings along the prom - soaking some spectators.
The Environment Agency has criticised those who had ignored warnings to stay away from coastal areas following a series of deaths.
'Clearly it is dangerous to get too close to these waves,' a spokesman said.
'There is colossal power in these waves that can knock people off their feet. We would advice people to keep well away.
'There have already been two fatalities this year already and urge you not to add to those statistics.
'Keep well away and if you are going to watch the waves keep up on high ground and well clear of the actual waves breaking over the sea front and promenades or anywhere you could be knocked off your feet.'
Tamsin Thomas, for the RNLI, added: 'This advice is being given out for a very good reason by the emergency services who are experts in these matters'.
Widespread flooding was reported in both counties with places such as Looe, Newquay, Instow and Kingsbridge all swamped in low-lying coastal areas.
In Salcombe, Devon, the high street was completely flooded and an RNLI lifeboat volunteer was seen paddling past the shops and businesses in a boat.
The surging waves also caused damage to coastal defences, with a massive piece of sea wall estimated to weigh over 100 tonnes torn from a sea wall in Portreath, Cornwall.
Winds and and driving rains made the region's roads treacherous and the busy A30 near Launceston, Cornwall, was closed in both directions when a car hit a tree.
A flash hail storm sparked a crash on the A38 where a driver was seriously injured.
In the South East, Yalding in Kent was deluged again overnight but not on the same scale as over Christmas, according to local reports.
The Little Venice caravan park was flooded again and around six nearby properties affected.
Jenny Donovan, from the Environment Agency, told BBC Radio Kent: 'Unfortunately there was flooding again in Yalding last night from the River Beult.
'We had people from the Environment Agency working closely with professional partners, the local authorities and the emergency services.
'It's going to be important for the next 24 to 48 hours that people remain vigilant. If we see the high ends of the rain that is forecast over the next 24 to 48 hours, we will see an increase in flood risk across the whole of the county.'
In the South East, 20 flood warnings and 90 flood alerts were in place at 8am. There were no severe flood warnings.
Sussex Police have warned of problems as more rain falls, adding to already swollen rivers.
Winds of up to 65mph along the coast, combined with high tides and low pressure, were likely to create storm surges, the force said.
The port of Dover in Kent was operating normally.
High risk areas include the densely-packed residential streets of Sydenham and Victoria Park in the east of the capital and around the docks.
Police Service of Northern Ireland (PSNI) Assistant Chief Constable Stephen Martin said: 'We are particularly concerned around a number of areas, those areas are Victoria Park in Belfast, the Sydenham area of Belfast and around the docks area of Belfast.
'We are working as much as we can to try and prepare ourselves for potential flooding in those areas so during the course of today we have distributed many thousands of sand bags.'
The latest storm has heaped more midwinter misery on travellers today with road journeys and rail services disrupted.
Many major roads were flooded, while trains to and from Gatwick Airport in West Sussex were among those affected by storm-related problems.
Some roads in Gloucestershire are now under flood waters, police said.
A spokeswoman for Gloucestershire Police said: 'The Severn Bore has now gone through Elmore and Minsterworth with reports that the water has overtopped the defences in some parts.
'The tidal surge will follow and is due to reach Gloucester around 11am today. All agencies are asking people to stay away from the water.'
The A48 is closed between Oakle Street and Elton Corner, while Northway Lane is Tewkesbury is 'impassable' due to flooding, she added.
There are reports that Goose Lane is Rodley is also impassable.
Gloucestershire Highways area manager Jason Humm said: 'We've had a fair amount of rainfall on saturated ground so there has been some surface water on the highways and we would urge drivers to continue to take extra care travelling around the county.
'We've had additional gangs on overnight and into this morning and the workforce will prioritise any flooding issues that may arise.
'Rising river levels have caused some issues with roads locally and we are anticipating further issues at the A417 in Maisemore.
'Gangs are fully prepared to react immediately if needed and we would encourage people to use alternative routes.'
Rest centres for concerned residents have been opened in Tewkesbury and the Forest of Dean.
Southern and south west England, Wales and Scotland bore the brunt of the adverse weather, while travellers whose services were running normally had to contend with wind and rain on the way to work.
Electrical supply problems at South Croydon in south London meant delays of up to 40 minutes on trains between Gatwick Airport and East Croydon, while a signalling problem at Dorking in Surrey led to hold-ups between Dorking and Leatherhead.
Pre-Christmas flooding has meant that no trains are able to run on the Isle of Wight, with services not expected to start again until well into January.
Earlier problems have also led to buses replacing trains between Petersfield in Hampshire and Haslemere in Surrey, with rail services not expected to resume until Sunday.
The bad weather meant there were also no trains today between Guildford in Surrey and Ascot in Berkshire, while flooding meant services were unable to operate between Paignton and Newton Abbot in Devon or between Liskeard and Looe in Cornwall.
In Wales, buses replaced trains between Pwllheli and Harlech and between Llanelli and Carmarthen where the line was blocked.
In southern Scotland, electrical supply problems between Carstairs and Lockerbie caused delays of up to 60 minutes, with Virgin's West Coast services among those affected.
A number of ferry services had to be axed, with others disrupted.
Cancelled services included Argyll Ferries crossings between Gourock and Dunoon and the P&O Irish Sea route between Cairnryan and Larne and between Troon and Larne.
British Airways and Virgin Atlantic were among carriers which experienced delays and cancellations to some transatlantic flights due to severe winter weather in the eastern USA.
BA said: We are operating a normal schedule from Heathrow today, both domestically and to the US.
We did experience some disruption to services to and from New York, Boston and Philadelphia yesterday and overnight, due to severe weather in the area.
'Our teams have been working extremely hard to help customers whose flights have been affected, offering alternative services or a full refund.'
A car has been swept into the sea at Portscatho after getting caught in a swollen stream. The driver managed to scramble to safety.
At Newquay, Fistral's beach bar has partly collapsed after sea defences were undermined by the pounding waves.
Floods shut roads in Fowey, Polzeath, Millbrook, Tresillian, Penzance and Looe, and in Saltash the water was lapping at the feet of the Brunel statue.
The Environment Agency is urging people to stay off the beaches and clear of the coasts, with fears that a deadly combination of 70mph winds and 20ft waves will add to the dangers of more high spring tides due over the next couple of days.
Mark Pilcher from the Environment Agency said 'We've got a big spring tide anyway, and that's coupled with this surge that is being pushed by the wind and the low pressure that will potentially compromise some of the coastal defences.
'People need to think about their location. Are they close to harbours? Are they in low lying parts of the coast? Are they in areas that they remember perhaps flooded in 2008 when we had a similar situation? And make preparations.
'Think about all the things you've had for Christmas, all your precious things get them upstairs. Think about how to look after yourself first and your property next.
'You've got to be safe. I know people like to go out and look at the drama of the waves but please please do not put yourself at risk.
'The wind will be strong the waves will be big and they will be very powerful. One mistake could be very, very serious. Please don't put yourself at risk.'
Up to four people have been swept away by powerful waves in recent days.
A search for a 27-year-old man dragged out to sea in Cornwall on New Year's Eve was called off yesterday when a body was found.
The man, from Surrey, had gone for a paddle with four friends in the sea at Loe Bar, near Porthleven.
A woman died when she was swept out to sea at Croyde Bay in North Devon on Tuesday morning.
Inquiries are continuing in Dorset for a man who is believed to have fallen into the Stour river near Christchurch in Dorset on Wednesday night.
And a 36-year-old woman is feared dead after she was seen being swept out to sea from the beach at Brighton before Christmas.
Weeks of heavy rain and saturated ground mean there is also an increased risk of rivers bursting their banks over the coming days.
In Gloucestershire, high tide on the River Severn was expected between 8am and 10am today and homes and businesses are at risk of flooding.
Three 'large' Severn Bores - when the tide from the Severn Estuary is forced into narrower channels upstream - have been predicted over the next 48 hours.
Simon McMillan, from Gloucestershire Fire and Rescue service, is also asking people to avoid the banks of the River Severn.
'We're asking those who were planning to watch the Severn Bore go through tomorrow morning, to avoid the area completely.
'The situation could change very fast and there is a real possibility you may get caught out.'
Chief superintendent Gary Thompson, of Gloucestershire Police, said: 'We're asking all drivers to avoid the roads close to the River Severn wherever possible.
'If the roads do flood, please avoid driving through the standing water as it maybe hiding debris or loose manhole covers.'
The AA warned that some drivers were failing to heed flood warnings, and that it has attended 1,500 call-outs from those stranded due to floods since December 23.
Thecall outs include patrols being sent to 400 vehicles stuck in flood water, while the rest were vehicles that broke down after being driven through the water.
In Sussex, police warned that winds of up to 65mph along the coast, combined with high tides and low pressure, were likely.
Inspector Andy Kundert, Sussex Police's emergency planning officer, said there was a potential for coastal and inland flooding around the high-tide times of midday and midnight today.
He warned people who may be tempted to swim or take a paddle not to, and said 'enormous amounts' of shingle had been washed away over the past few weeks, meaning the sea has been pushing further up the beaches.
People were urged to look out for their neighbours, particularly if vulnerable. Mr Kundert said: 'All the emergency services, local authorities and other agencies will be working to make sure the county is as safe as possible.'
The coastguard was yesterday still searching for a man who is believed to have fallen into the River Stour in Christchurch, Dorset.
Portland Coastguard led the search near Iford Bridge from 7pm on Wendnesday and a rescue helicopter, inshore lifeboat and the Wick ferry were called to help the emergency services.
Jennet Chisholm, Portland Coastguard watch manager, said last night: 'All the rescue units are working in very challenging conditions with rain and strong winds, but so far have been unable to find any sign of a missing man.'
Visitors to coastal areas have been warned to stay out of the sea, while those inland have been braced for localised flooding. An annual fund-raising swim at Gosport in Hampshire was cancelled on Wednesday as high winds and heavy rains hit the south coast.
Flood-stricken: The Sunny Sands Caravan Park in Barmouth west Wales, is completely under water today
Roads have been closed, while around 300 properties in the south and east of England were on Wednesday night left without electricity.
UK Power Networks said today its engineers had restored all supplies in the Great Yarmouth area after a large tree was removed from an overhead line.
The A36 was closed northbound between the junctions with the A3090 before being reopened this morning and the A27 in Hampshire due to flooding, and is expected to reopen from 6am.
Flooding affected a number of train services yesterday morning.
South West Trains said flooding meant no services were running between Teddington in Richmond, south-west London, and Shepperton in Surrey.
Replacement buses were brought in and are accepting rail tickets.
There was also a reduced service between Redbridge in east London and Romsey in Hampshire, and disruption between Fareham and Southampton Central and Easleigh in Hampshire, because of flooding at Hedge End and Botley, Southern said.
There were also delays between Gloucester and Swindon and between Taunton in Somerset and Westbury in Wiltshire.
South West Trains said there were no services between Portsmouth and Fareham in Hampshire because of electrical supply problems.
STORM SHOWERS SOUTH-WEST WITH SPROUT-SIZED HAILSTONES
Hailstones the size of sprouts
Hailstones as big as sprouts caused skidpan chaos on the M5 in Devon and Somerset this morning with dozens of cars, lorries and motorbikes caught up in a series of smashes.
Luckily, drivers had slowed to a crawl because the hail reduced visibility to a few yards and rescue services reported there were only bumps bruises and shock.
A spokesman for the ambulance service said 'Following the hail storm just south of Cullompton there were cars skidding all over the motorway, both northbound and southbound.'
Emergency services raced to the scene of the chaos and collisions, which happened between junction 28 and 29.
The Highways Agency said the smashes had caused a big build-up of traffic in both directions and conditions have been made worse by huge 'lakes' of standing water on the motorway.
Meanwhile the region continues to be lashed by heavy rain and thunder.
These people are still being hit very hard. My thoughts are with them.