The Environment Agency has issued a severe flood warning for the whole of the Devon and Cornwall coast amid storm warnings for south and west Britain.
Severe flood warnings have been issued for the Devon and Cornwall coast amid storm warnings for most of the UK.
Large parts of England and Wales are braced for what experts warn may be the worst storm of the winter.
Experts warn England and Wales could be hit by winds of up to 80mph (130km/h) on Monday and Tuesday, in what may be the worst storm of the winter.
The Met Office issued severe weather warnings for much of the UK, with winds of up to 80mph (130km/h) expected.
The Met Office also forecasts blizzards and heavy snow for central Scotland.
Forecasters said storms on Monday and Tuesday could disrupt travel and bring down power lines and trees.
About 170 people have been told to evacuate a caravan park in south Wales and some ferry crossings have been cancelled amid fears of storms at sea.
The agency is urging people to stay away from exposed coastal areas and to check for flood warnings in their area.
The Environment Agency is urging people to stay away from exposed coastal areas and to check for flood warnings in their area.
We understand that people are fascinated by the sea but at times like this we do urge them not to go and watch the high waves Paul LeinsterEnvironment Agency
Cancellations
The agency's director of operations, Paul Leinster, said: "There will be a potent cocktail of strong winds, wave action and high tides from Sunday night through until Wednesday."
By 2345 GMT on Sunday there were seven severe flood warnings in place in Devon and Cornwall and 44 other warnings in locations including southern England, and the Severn and Mersey estuaries.
He said that gale force winds were expected to combine with spring high tides to raise water levels along the coast by up to 1.5 metres over normal levels.
In parts of Wales and south-west England, gusts of about 55mph (90km/h) were recorded and some heavy rain had started to fall.
Mr Leinster said: "We understand that people are fascinated by the sea but at times like this we do urge them not to go and watch the high waves - it is extremely dangerous and only takes a few seconds for someone to be knocked off their feet, into the water."
By 2200 GMT on Sunday there were seven severe flood warnings in place in Devon and Cornwall and 37 other warnings in locations including southern England, and the Severn and Mersey estuaries.
In parts of Wales and south-west England, gusts of about 45mph (72km/h) were recorded and some light rain had started to fall.
FLOODLINE Call 0845 988 11 88
Ferries between Portsmouth and Bilbao in Spain have also been cancelled because of fears of severe storms at sea.
P&O Ferries said it had cancelled its Sunday sailing from Portsmouth to Bilbao, and from Bilbao to Portsmouth on 11 March.
P&O Ferries said it had cancelled its Sunday sailing from Portsmouth to Bilbao, and from Bilbao to Portsmouth on 11 March.
The company's website also said sailings between Dover and Calais are being delayed by up to an hour because of the weather conditions.
FLOODLINE Call 0845 988 11 88
Senior government officials met on Sunday afternoon to discuss the threat from the storm and to check that local authorities were prepared for floods.
The company's website also said sailings between Dover and Calais were delayed by up to an hour because of the weather conditions.
A spokesman for Gatwick airport said if the weather was as bad as predicted, travellers could face delays or cancellations.
Ministerial concern
Ministerial concern
BBC political correspondent Ben Wright said he understood that Prime Minister Gordon Brown joined the meeting by telephone and "intervened once or twice".
Prime Minister Gordon Brown and senior government officials held talks on Sunday afternoon about the threat from the storm and checked local authorities were prepared for floods.
Ministers are said to be most concerned about floods around dawn, when sea tides are at their highest.
Ministers are said to be most concerned about floods around dawn, when sea tides are at their highest.
In Pembrokeshire and Cornwall, emergency planning were preparing for high winds and floods. Stand-by supplies of sandbags are being provided and extra police called in to work overnight Sunday and from early Monday.
Cornwall's emergency planning officer Steve Winston said a combination of factors, including high spring tides and a very low pressure system, could lead to a "severe" event.
Huge waves are expected to hit the UK coast.
Huge waves are expected to hit the UK coast.
BBC weather forecaster Peter Gibbs said a storm of this ferocity usually occurs once a year.
Police in south Wales have advised people at a caravan Site in St Brides, Newport, to evacuate their homes because of possible flooding and structural damage.
Much of the severe weather this winter had hit the north of Britain, whereas this storm would affect the south and the west, he added.
In nearby Gold Cliff and Redwick, residents in coastal homes were also advised to evacuate.
Martin Young, chief forecaster at the Met Office, said: "It will be very windy for many parts of the UK in the early part of next week, but especially so across coasts in the south.
Newport Leisure Centre has been set up as an evacuation rest centre by the city council.
"Southerly winds are expected to strengthen during the early hours of Monday causing severe gales.
In west Wales, the worst hit areas were expected to be Amroth, Newgale, Dale, Solva and the centre of Haverfordwest in Pembrokeshire.
"After a brief respite, further westerly severe gales are forecast for later in the day and into the early hours of Tuesday."
We understand that people are fascinated by the sea but at times like this we do urge them not to go and watch the high waves Paul LeinsterEnvironment Agency
Damage is expected across the county from high winds and there may be further evacuations in some areas at risk of flooding.
In Cornwall, emergency planning teams were preparing for high winds and floods.
Stand-by supplies of sandbags were being provided and extra police called in to work overnight Sunday and from early Monday.
Cornwall's emergency planning officer Steve Winston said a combination of factors, including high spring tides and a very low pressure system, could lead to a "severe" event.
The Environment Agency urged people living in low-lying exposed coastal areas of Wales, south-west and southern England, including Hampshire, the Isle of Wight, Sussex and Kent to monitor the weather closely.
High waves
The Met Office advised travellers to leave extra time for journeys, as rail delays were likely, with the worst weather expected to strike during on Monday afternoon.
The RAC advised drivers to be prepared for hazardous driving conditions over the next few days.
The Environment Agency's director of operations, Paul Leinster, said: "There will be a potent cocktail of strong winds, wave action and high tides from Sunday night through until Wednesday."
He said that gale force winds were expected to combine with spring high tides to raise water levels along the coast by up to 1.5 metres over normal levels.
Mr Leinster said: "We understand that people are fascinated by the sea but at times like this we do urge them not to go and watch the high waves - it is extremely dangerous and only takes a few seconds for someone to be knocked off their feet, into the water."
Do you live in the regions which could be affected by the storms? How are you preparing? Send us your experiences using the form below.
Do you live in the regions which could be affected by the storms? How are you preparing? Send us your experiences using the form below.
