Insurers could have to pay out up to 345 million euros in claims, after Storm Desmond left swathes of northern England and Scotland under water.
More than a month’s rain has fallen over 24 hours in some areas, with the counties of Cumbria and Lancashire badly affected.
At least two people have died, hundreds have been forced out of their homes and power has been cut – affecting tens of thousands.
British Prime Minister has chaired an emergency government meeting to coordinate the emergency response.
He also visited the town of Kendal, one of the towns worst hit by flooding in the north of England.
Cameron met rescue workers and soldiers, and was shown the damage caused by flooding to a woman’s house.
“The people who have got to move out of their homes, we need to get their insurance claims done quickly, find them alternative accommodation,” the prime minister said.
“Emergency services have been brilliant, but that’s no consolation to people who, you know, face a very wet few days, perhaps not being home for Christmas.”
Some in the northwest, which was also badly flooded in 2009 and 2005, have criticised flood defences.
But Environment Agency Chief Executive James Bevan described the recent weather has an “unprecedented event.”
“In those areas where the water did come over the tops of the defences, firstly, the fact the defences were there reduced the overall impact and extent of the flood and, secondly, it gave people more time to prepare,” he said in an interview.
“From time to time, nature will throw things at us, which will overwhelm the system and I think that is what happened here.”