More than 1,000 people have been forced to flee their homes, with many more braced to evacuate in the coming days as weeks of heavy rainfall shows no signs of abating.
Hundreds of military personnel have been drafted in to help in the worst-affected areas of south west England and the Home Counties, as politicians and agencies get embroiled in a war of words prompted by residents' anger at a perceived lack of action.
Around 400 weather warnings remain in place across England, with forecasters predicting further heavy rainfall on already-saturated ground.
In some cases, desperate home-owners reported having their vacant homes looted, while others said sandbags intended for the worst-hit areas were "hijacked".
It comes as senior politicians continue their fact-finding tours of deluged communities, pledging that authorities are doing "everything possible" to repair damage and prevent further destruction.
Last night more than 70 people were evacuated from their homes in the Thames Valley - tipping the number over the 1,000 mark since the end of January.
Communities Secretary Eric Pickles told MPs there was a high risk that the River Severn and River Wye would also break their banks, further stretching resources.
The Met Office's Sarah Davies told a briefing that strong winds forecast for the middle of the week could add to the problems facing the country - with snow reported today in pockets of the Midlands.
Some 20-40mm (0.75-1.5 inches) of rain is expected by Friday night across many southern and western areas.
But some regions, including the already flood-hit south west of England, South Wales, western Scotland and Northern Ireland could have up to 70mm (2.75 inches).
A storm due to hit tomorrow could fell trees and cause transport and power disruption, Ms Davies warned, with winds in the South West potentially reaching 80mph.
Prime Minister David Cameron spent the morning in the Devon resort of Dawlish, which has seen its railway track destroyed, cutting off the rail link between Cornwall and the rest of the country.
He said it was "going to take time before we get things back to normal" but ministers would do everything possible.
"It is a huge challenge and we have had the wettest start to a year for 250 years, some of the most extreme weather we have seen in our country in decades," he said.
Defence Secretary Philip Hammond was tackled by residents in the Berkshire community of Wraysbury, who said they were "seriously in need" of military intervention.
Mr Hammond told the BBC that the "Government has got a grip on this" but authorities cannot "prevent the course of nature".
He told BBC Radio 4's Today programme: "We are dealing with an enormous force of nature here, vast quantities of water, an unprecedented weather pattern, and, while the authorities can and must do everything that is possible, there are some things I'm afraid that we just can't do.
"We cannot always intervene to prevent the course of nature."
Mr Hammond, whose constituency of Runnymede and Weybridge has been affected by the flooding, said now was not the time to discuss how well the Environment Agency has dealt with the situation.
He told BBC Breakfast: "Of course the Environment Agency - obviously under enormous pressure - is doing everything it can to manage this situation.
"Of course there will be longer-term questions about policy on the way flooding defences are managed, on, for example, the policy of river dredging, and the time to discuss them is when the waters have gone down, when we've gone back to normal."
The Ministry of Defence said hundreds of military personnel were involved in attempts to help beleaguered communities.
A spokesman said 100 men from HMS Sultan spent last night working near Windsor in Berkshire, while 200 from HMS Collingwood and HMS Sultan were packing sandbags destined for the Thames Valley.
One hundred men from 7 Battalion the Rifles and members of the 9 Transport Logistics regiment spent last night protecting the electricity substation at Pingewood in Berkshire.
In Eastbury village, Berkshire, 34 members of 7 Battalion the Rifles worked through the night to fill sandbags and help repair flood defences.
Their number has been boosted by an army of volunteers who have pitched in to help with the operations in the Thames Valley.
Meanwhile, commuters faced another day of delays on the rail networks.
There is major disruption to CrossCountry services between Oxford and Didcot Parkway, Bridgwater and Taunton, and Taunton and Plymouth/Penzance, while First Great Western said it would only be able to run four trains an hour between Reading and London Paddington because of flooding near Maidenhead.
South West Trains, Southeastern and Southern are also operating heavily-curtailed services.
Communities Secretary Eric Pickles said special efforts were being made to protect vital infrastructure from the floods to minimise disruption.
But officials have predicted hundreds more homes will be flooded over the coming days and restoring the country's battered rail network could take months.
Mr Pickles chaired the latest meeting of the Government's Cobra emergency committee yesterday as the Prime Minister visited south west England.
He warned: "Sadly, the worst of the bad weather is not over. But we are working tirelessly to deal with the situation on the ground and to prepare and protect vulnerable areas."
Efforts to deal with the flooding have been overshadowed by a bitter clash between ministers and the Environment Agency, after Mr Pickles issued a barbed apology for relying on its advice.
Environment Secretary Owen Paterson - who was leading the response until being forced to undergo an eye operation - is said to have complained to Downing Street over his Tory colleague's intervention.
Mr Pickles sought to make light of a supposed rift, describing Mr Paterson as his "brother from a different mother" after being summoned to the Commons to respond to an urgent question.
The Prime Minister, on a visit to Chesil Beach yesterday, praised the work of the Environment Agency but gave only limited support to its under-fire chairman Lord Smith, saying "this isn't the time for a change in personnel, this is the time for getting on, everyone has to get on with the job they are doing".
Mr Cameron said he would hold a press conference at Downing Street to discuss the response to the floods.
He wrote on Twitter: "After a day visiting flood-hit areas, I'll update the country on the latest plan of action with a press conference at No 10 at 4:45pm."
Explaining the purpose of Mr Cameron's visits to flood-hit areas, the PM's official spokesman told reporters: "It is about the Prime Minister seeing for himself and getting the fullest possible picture from those on the ground - those affected, the respondents supporting the communities - and understanding the situation they face as part of the wide-ranging work to ensure that we are doing all we can to help the affected communities."
Asked if the PM wanted to show solidarity with those affected by the floods, the spokesman said: "Yes, of course part of it is demonstrating that at the very highest levels of Government, the Government is determined to understand the full impact of the recent storms and flooding so we can bring to bear the greatest possible assistance."
Mr Cameron stayed overnight in a hotel in Exeter and postponed this morning's scheduled weekly meeting of Cabinet to continue his visit to the South West for a second day. He is expected to chair a meeting of Cobra in Whitehall this evening.
The spokesman confirmed that 1,600 troops were available for deployment to assist communities, with hundreds in action at some points during the crisis.
The PM's spokesman was asked at a regular Westminster media briefing whether Mr Cameron would consider diverting money from the UK's £11 billion foreign aid budget to help people affected by floods.
The spokesman responded: "As the Prime Minister was saying yesterday, the resources are there. That is the central point.
"When more pumps were needed, more pumps were provided. When the military were needed, the military was deployed. We've told councils that they can spend the money that they need to and we will reimburse them. We have made available £130 million more in the announcement last week for repairs and maintenance.
"So we can very clearly say that the resources are there."
Labour leader Ed Miliband said flood defences should be made a higher priority for Government, even if it costs more money.
Asked during a visit to Wraysbury whether he would spend more on defences, Mr Miliband told the BBC: "Yes. It's clear - and it was clear from the Pitt Report that was commissioned after the 2007 floods that happened under the last Labour government - that more needed to be done on flood defences.
"We can't attribute any one event to climate change, but we know climate change is going to mean we have more events like this - more extreme weather events, more flooding, more storms.
"It's clear that flood defence needs to be more of a priority for Government."
Mr Miliband was asked whether he accepted that making flood defence a higher priority would be expensive. He responded: "Yes, but not dealing with it is even more expensive.
"If there's one thing we know about the effects of extreme weather, it's that the costs - financial, human and other costs - of not acting are much greater than the costs of acting. It's a totally false economy to say 'Don't act'. The Government's got to realise this and it's got to take the problem seriously."
The Labour leader urged ministers to stop "finger-pointing" and focus on getting assistance to communities affected by floods.
"I think it's clear that the game is now being raised in terms of the help being provided, and that's obviously important," said Mr Miliband.
"I think finger-pointing is not what the Government should be doing, it's rolling their sleeves up and getting on with getting people the help, making sure that all the necessary agencies are working together, all the help is being provided for people.
"One of the most important things at a time like this is that people feel supported. People in this area and areas like it need to feel that the authorities - all of the authorities - are doing everything they can to help them."