Lifeboat crews from across the South were today joining a major rescue operation after floods caused millions of pounds of damage to homes and businesses.

RNLI volunteers from Poole, Shoreham, Brighton, Eastbourne and Hastings were on their way to help flood victims in Uckfield, worst hit town in the South East and which is also threatened by an incoming tide.

Five inflatable lifeboats and more than 20 members of the RNLI will help carry people from their flooded homes and shops to rest centres throughout the town, which was devastated when the River Ouse burst its banks last night.

Earlier today a shopkeeper was swept away by fast flowing floods in Uckfield. A search was launched at 7.20am. Twenty minutes later he was spotted in the River Uck clinging on for his life, cold and shivering and rescued by coastguard helicopter.

The RNLI itself became a victim of the floods when its regional fund-raising offices in River Way, Uckfield, had to be evacuated.

Among people stranded at home was Glyn Davies, 49, from Uckfield, who said: "Last night we had rain coming in through the roof and it leaked into the loft and our bedroom.

"We are really concerned, especially as they have forecast more rain later.

"We are quite lucky as we are reasonably high up, but just one minute's walk away everything is flooded, so we are stuck here."

Peter Vince, a 27-year-old warehouse distributor from Hadlow Down, said: "Out the back of my house was flooded this morning and just down the road the water was at least 3ft deep.

"I wasn't too worried about water getting into my home as I had cleared the drains, but because we are so close to the River Uck we have been stranded today and can't get to work.

"The river has flooded everything, including the fields, and everything is soaked."

The Environment Agency also began evacuating people in Lewes near the River Ouse, one of many rivers in Sussex for which severe flood warnings have been issued.

Similar warnings are in place on the River Uck at Uckfield and the River Medway between Forest Row and Penshurst.

Hassocks, Haywards Heath, Goring, Arundel and Steyning are all badly flooded.

Etchingham station, near Hastings, was evacuated due to flooding. About 30 cars in the station car park began floating and crashing into each other.

In Robertsbridge, shopkeepers and homeowners in the high street are being evacuated with the help of a coastguard team from Pett.

The RSPCA issued an urgent warning to farmers and pet owners to protect livestock and ensure they were not cut off by rising flood water.

Inspectors rescued 25 sheep stuck in a flooded field at Ansty, near Haywards Heath. In Polegate a bullock had to be rescued from a field.

Police urged drivers to stay at home as main roads, including the A21, A22, A26, A27, A227 and A272, were flooded.

Drivers of four-wheel-drive vehicles were asked to go to the aid of stranded motorists, many of whom have been forced to sit on the roofs of their cars.

The Met Office warned there was more rain to come throughout today but said showers would ease on Friday.

Official figures confirmed more than 100mm (3.9in) of rain has fallen in the South East during the last 24 hours.

Ewen McCallum, head of forecasting at the Met Office, said: "The situation is likely to get worse today before things start to improve overnight."