Rain coupled with high tides and strong winds made it particularly dangerous along the coast, where estuaries were in danger of overflowing.
"At the same time the risk of river flooding continues for the southern counties as with the ground already saturated, rivers are very responsive to rainfall," said Environment Secretary Owen Paterson. "Groundwater levels also remain high in southern counties."
The BBC said five severe flood warnings were in effect in Cornwall and near Gloucester. Lesser advisories were posted in western Wales and the Somerset Levels.
Britain has been slogging through a wet and wild winter. The BBC said the government's emergency planning committee known as Cobra, which Paterson chairs, has met 16 times since a series of storms began rolling through in December.