Hundreds of homes have been swamped by floods along the Thames River, while British Prime Minister David Cameron warns that stricken communities are “in it for the long haul”.

The floods played havoc with rail travel, with one of Britain’s busiest routes, from London to the commuter town of Reading, heavily disrupted.

Affluent towns and villages along the Thames to the west of London have been transformed into lagoons, as the government faced renewed criticism it was under-prepared.

More than 1000 homes have been evacuated along the Thames, in villages and towns such as Wraysbury, Datchet and Chertsey, and the situation was set to worsen with heavy rain and storms on the way by Friday.

A total of 1600 troops are on standby to help, and some were already at work filling sandbags in Wraysbury, where one resident had a bitter exchange with Defence Secretary Philip Hammond.

Su Burrows, a volunteer flood warden, said the relief effort had been left to residents like her and pleaded with Hammond for military help to distribute sandbags.

“I’m sorry, I am going to get emotional. There are 100 people of this village currently working together, none of them (Environment Agency) agents, not one,” she told him in the exchange on Sky News television.

Burrows said later her blast seemed to have borne fruit, as 2000 sandbags were sent to Wraysbury, followed afterwards by 100 soldiers.

Cameron saw for himself the damage to the railway line at Dawlish in southwest England, caused by massive waves crashing against the coastline.

Train services have been cut off by the damage.

“It is a huge challenge and we have had the wettest start to a year for 250 years, some of the most extreme weather we have seen in our country in decades,” Cameron said.

“We have to recognise it is going to take time before we get things back to normal.”

Insurers said overall claims had already exceeded STG500 million ($A921.49 million) and the bill would rise fast.