Britain's flooding crisis prompted Deputy Prime Minister John Prescott to call an emergency meeting with senior government ministers on Saturday morning to discuss flood measures.
People are being urged to use the respite in the weather to restore flood defences, especially in York where the swollen River Ouse reached its highest level since records began.
Forecasters say the bad weather will return on Sunday, threatening areas such as Gloucester, where emergency services are on high alert.
The chief executive of the Environment Agency, Ed Gallagher, said: "There is a lot more grief to come."
He praised the work of his staff, the emergency services and hundreds of volunteers who have worked for several days to prevent the damage getting worse.
Britain's flooding crisis prompted Deputy Prime Minister John Prescott to call an emergency meeting with senior government ministers on Saturday morning to discuss flood measures.
Junior agriculture minister Elliot Morley warned as he left the meeting: "It's not over yet."
"There's more rainfall to come so we can't be complacent.
"The warnings have worked well nationally. The response has been good."
A massive civil emergency operation was launched in York on Friday.
Flood defences there have been reinforced with sandbags by the Army throughout the night and into Saturday.
'Window of opportunity'
Police Chief Superintendent Gary Barnett spoke of a "window of opportunity" for the city in which the emergency services hope to improve the situation before the next heavy rain fall which is forecast for Sunday night.
He said: "We are on a knife-edge at the moment and it doesn't look like it's going to change for the next two or three days yet.
"I must stress we are not out of the woods yet. The water is still very high and the flood defences have never been put to such an exhaustive test as they are being put to now."
Thousands of homes have now been swamped across Britain and the torrent of water is on the same scale as the "Great Floods" of 1947.
By Saturday the worst flooding had moved on from Worcester and Tewkesbury and Gloucester was under threat.
There are more than 100 flood warnings throughout England and Wales, though waters are receding in most areas.
More downpours
Another low pressure weather system is expected to hit Britain on Sunday, bringing more rain and strong winds.
The saturated ground and swollen rivers will struggle to cope with more rain and further floods are considered inevitable.
South-east England in particular has been placed on high alert. It is feared there could be as much as two inches of rain over a 48-hour period.
The River Severn is still causing concern, although Shrewsbury and Worcester have escaped relatively unscathed.
A spokeswoman for Gloucester Prison said managers were keeping a close eye on river levels close by and had contingency plans for the evacuation of inmates if necessary.
And more problems have been caused by hundreds of sightseers coming into Gloucester to see the floods.
They are being advised to go home and monitor the developments on television.
The Environment Agency predicts flood levels on the Severn will peak in Gloucester in the early hours of Sunday morning.