'Worst storm in years' to strike
The worst storm for more than five years is expected to batter England and Wales on Sunday night and Monday morning.
The Met Office said winds in excess of 80mph could bring down trees and cause structural damage, leading to power cuts and transport disruption in rush hour on Monday morning.
The Environment Agency warned of surface water flooding incidents across most of England as forecasters predicted 20-40mm of rain could fall within six to nine hours.
Insurance companies have advised households to take steps to protect themselves and their property.
These include establishing an evacuation plan, ensuring gutters are clear so water can drain effectively and placing valuable items upstairs to limit flood damage.
The storm will develop over the Atlantic and is expected to hit the south-west of Britain before moving north-eastwards. Heavy rain is due to arrive on Sunday night with strong winds in the early hours of Monday, and the storm is expected to be out over the North Sea later that day.
It has been named the St Jude Storm after t he patron saint of lost causes, whose feast day is on Monday.
The Met Office issued an amber warning, meaning ''be prepared'', for the southern half of England and the southern half of Wales.
It gave a lesser yellow warning, meaning ''be aware'', for the rest of Wales and England up to the border with Scotland.
The Met Office described the storm as not one "you would see every year", and said the expected wind strengths would be similar to storms in March 2008, January 2007 and October 2000.
Frank Saunders, chief forecaster at the Met Office, said: "We are confident that a severe storm will affect Britain on Sunday night and Monday. We are now looking at refining the details about which areas will see the strongest winds and the heaviest rain.
"This is a developing situation and we'd advise people to stay up to date with our forecasts and warnings over the weekend, and be prepared to change their plans if necessary. We'll continue to work closely with authorities and emergency services to ensure they are aware of the expected conditions."
Atlantic storms of this type usually develop further west across the ocean, losing strength by the time they reach the UK and Ireland.
But this is expected to appear much closer to land, potentially moving across the country while in its most powerful phase.
A strong jet stream and warm air close to the UK are contributing to its development and strength.
Gemma Plumb , a forecaster with Me teoGroup, the weather division of the Press Association, said: "The first place that will see the strong winds will be south-west England, which could see gusts of 75-80mph.
"The storm will move north-eastwards, with winds of 60-70mph in the Midlands and East Anglia.
"Northern England and North Wales are looking at winds of 50-60mph."
An Environment Agency (EA) spokesman said: "EA teams are out working to minimise river flood risk, clearing debris from streams and unblocking culverts. We will continue to closely monitor the situation ready to issue flood warnings if needed. We are supporting local authorities who will respond to any reports of surface water flooding.
"Seafronts, quaysides and jetties should be avoided due to the risk of overtopping by waves and wind blown shingle."
Martin Hobbs, head of asset resilience at the Highways Agency, said: " Be aware of sudden gusts of wind and give high-sided vehicles, caravans, motorbikes and bicycles plenty of space."
Home insurers were bracing themselves for the prospect of a high number of storm damage claims.
Claire Foster of Direct Line said: "We take the current severe weather and flood warnings extremely seriously and have put our emergency action plans into place. We have people on the ground and on the phones ready to help customers make a claim.
The forecast of storms has also caused the cancellation of f erry services on Sunday and Monday between Plymouth and Roscoff as well as Penzance and the Isles of Scilly.
Brittany Ferries, which runs the Plymouth-Roscoff route, said on its website: " We are in the process of contacting all passengers booked on these sailings. We apologise for the inconvenience the cancellation of these services will cause."