Torrential rain of "biblical proportions" caused serious flooding across northern England and southern Scotland today as searches intensified for a police officer who went missing after a bridge collapsed.

Flood defences in Cumbrian towns were overwhelmed by unprecedented downpours that officials said could be expected only once in a thousand years.

The Meteorological Office said the amount of rain expected during the entire month of November had fallen in 24 hours, with the Environment Agency reporting 314 mm had fallen in one area which it said was a record for England.

"It was described to me this morning, this particular flood, as of biblical proportions," said Tony Cunningham, MP for Workington, one of the worst affected towns.

"That gives you some idea of the scale and the force of the devastation," he told Sky News.

Lifeboats and Royal Air Force helicopters were used to rescue hundreds of people from their homes in towns and villages across the picturesque Lake District.

The Ministry of Defence said military help was being provided and could be stepped up while Cumbrian police said a search was continuing for a police officer who disappeared when a bridge collapsed under the weight of water.

Emergency services said they were also concerned about another 10 properties in the town of Cockermouth they had been unable to reach, while media reports said some trapped residents had been forced to smash through their roofs to escape.

"This is an extremely serious incident. We have seen unprecedented rainfall," said Environment Agency Chairman Chris Smith.

Britain has been hit by severe flooding in recent years, raising questions about the impact of global warming. Last year Britain saw its wettest summer since records began in 1914 while floods in 2007 affected 55,000 homes and businesses and left an insurance bill of around 3 billion pounds.

The Met Office said there was a better forecast for Friday but another 40 mm of rain could fall tomorrow.

Officials said there were four severe flood warnings -- where there is extreme danger to life and property -- for northwest England and another eight in Scotland.

One witness in Cockermouth told BBC radio he saw the water level rise rapidly from his top floor window.

"In the space of about 5 minutes, from there being puddles on the main street there was about an inch of water right across it, and then it rose very quickly.

"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."