Lifeboats and military helicopters rescued hundreds of people overnight in northern England and a policeman was killed as torrential rain flooded homes, washed away bridges and closed roads.
Police in the picturesque Lake District county of Cumbria, a magnet for tourists, said Friday they had found the body of the officer who was swept away when a bridge collapsed.
"Police Constable Bill Barker died trying to save the lives of others. He was a very heroic, a very brave man," said Prime Minister Gordon Brown, who promised emergency help for affected areas.
Barker, 44, a father-of-four who was due to celebrate his birthday Saturday, had been directing motorists away from the bridge when it caved in.
The Environment Agency said it was a "1-in-1,000-year" flood and 314 mm (12.4 inches) had fallen within 24 hours in one area, a record for England. The Meteorological Office said the amount of rain expected for all of November had fallen in one day.
Britain has been hit by severe flooding in recent years, raising questions about the impact of global warming. Last year the country saw its wettest summer since records began in 1914. Floods in 2007 affected 55,000 homes and businesses and left an insurance bill of around 3 billion pounds ($5 billion).
A spokesman for the Association of British Insurers said the latest floods appeared less destructive but it would take several days to make a reliable estimate. Police estimated about 1,000 homes in Cumbria had been damaged by the latest floods.
The Met Office said Friday's forecast was better but another 40 mm (1.6 inches) of rain could fall Saturday. Officials issued four severe flood warnings -- meaning extreme danger to life and property -- in northwest England, and two in Scotland.
A witness in the Cumbrian town of Cockermouth, birthplace of poet William Wordsworth, told BBC radio he saw the water level rise rapidly from his top floor window. "Within a very short space of time people were wading knee deep and then belly deep. And it was going up so fast it actually got very scary."
Ireland's Defense Forces said they were deploying 110 soldiers, 15 trucks and four boats to battle floods in the south and west of the country. Many homes and businesses were flooded in the country's second city, Cork.