London - Princes William and Harry pitched in for flood victims on Friday as a new winter storm barrelled towards Britain, threatening fresh misery after the wettest start to the year for 250 years.
The princes joined soldiers distributing sandbags to protect properties in the flood-hit village of Datchet, in the shadow of Queen Elizabeth II's Windsor Castle residence.
The royal relief came as the Met Office said a "multi-pronged attack" of wind, rain and snow was sweeping across the country after making landfall in southwest England.
It said up to 40mm of rain could fall on Friday as officials warned of huge waves on England's south coast as high tides combine with 128km/h winds.
Around 16 000 people also remained without power following an earlier storm on Wednesday when hurricane-force gales left one person dead.
Prime Minister David Cameron reiterated his promise to do "whatever it takes" to help stricken communities.
"Obviously, we are facing a very difficult time because we have got the wettest start to the year for 250 years and these are extraordinary weather events, but we are fighting on every front to help people," he told private broadcaster ITV.
More than 5 800 properties have been flooded since early December while huge swathes of farmland have been inundated, putting Britain's fragile economic recovery at risk.
Around 1 000 houses more were evacuated along the River Thames and in western England on Friday.
The swollen Thames was expected to reach its highest level for 60 years at the weekend, promising fresh misery for flooded towns.
In the Thamesside village of Datchet, second-in-line to the throne Prince William and his younger brother Harry donned Wellington boots and waterproofs as they lugged sandbags alongside members of the Household Cavalry.
"The Duke and Prince Harry wanted to show their support to the flood victims and thought the most appropriate way of doing that was through the armed forces relief effort," a Kensington Palace spokesperson told AFP.
Buckingham Palace meanwhile said the queen was helping farmers in the southwestern county of Somerset - parts of which have been underwater for nearly two months - by contributing feed and bedding from the royal farms at Windsor.
A total of 17 severe flood alerts indicating a risk to life are in place across Britain: 14 in Berkshire and Surrey to the west of London, two in Somerset and one in Gloucestershire, western England
Floodwaters were also rising in the cathedral city of Winchester and market town of Romsey in southern England, although waters that threatened the historic city of Worcester in central England receded slightly.
Cameron has said he will seek financial aid from the European Union to cope with the floods, despite his promises to renegotiate London's relationship with Brussels and hold a an in-out referendum.
"There is assistance that we are seeking from the EU," he said. "Some of the money I'm making available for Britain's farmers comes out of an EU budget."
His government has faced criticism for being slow to help people in flood-hit areas.
Emergency efforts were picking up following criticism of a sluggish response, and the military said 1 600 soldiers had been deployed with 2 000 in total available.
Train operator Network Rail said teams armed with chainsaws and pumps were on standby to deal with Friday's forecast storm.
Britain also faces an economic battering after Bank of England governor Mark Carney said the fragile recovery from recession would be affected as the bad weather hits farming and transport.
Cameron has said that money is "no object" in the relief effort.
He also said grants of up to £5 000 would be available to businesses and home owners affected by flooding to allow them to protect their properties better in future.