The military are being drafted into the Somerset Levels this evening - as forecasters warn of further torrential downpours overnight.
Royal Marines will assist with sand bag defences in the flood-hit region, which has been told to expect between 30mm and 40mm of rainfall between this evening and tomorrow morning.
Severe weather alerts have been put in place for south east England, the south West and Wales overnight. Parts of Somerset and Dorset could be hit by up to 20mm of rain in just two to three hours.
Residents are being evacuated from Northmoor, Fordgate and Saltmoor on the Levels, with many set to spend the night in an emergency rest centre in Bridgwater.
Environment Agency chairman Lord Smith will visit the Somerset Levels tomorrow, in his first trip to the region since it was hit by the floods.
An MOD spokesman said: "We can confirm that around 40 Royal Marines from 40 Commando based in Taunton have been deployed to affected areas to provide general flooding assistance. This assistance will support a range of tasks, including sandbagging and moving householders' property to higher levels.
"As part of the Government's overall response, the Ministry of Defence will continue to consider requests for military support positively and stands by to scope requests for assistance rapidly. We will continue to offer advice on specific roles where the military could provide assistance."
A spokesman for Avon and Somerset Police said a new emergency rest centre had been opened in Westfield Church, West Street in Bridgwater.
"People living in these areas have been advised by Avon and Somerset Police to leave their homes," the spokesman said. "This centre replaces the rest centre in North Petherton.
"Concerned residents are also being reminded that sandbags are available free of charge through district councils for people whose homes are at risk of flooding."
Two severe flood warnings - meaning a "danger to life" - have been issued by the Environment Agency.
The first is in Salt Moor and North Moor including East Lyng, Burrowbridge, West Yeo, Moorland and Fordgate, while a second relates to the A361 road from East Lyng to Burrowbridge.
Across the country, 75 flood warnings, requiring "immediate action" have been issued, with a further 257 flood alerts in place.
The Met Office has issued an amber warning for rainfall in south west England and London and south east England.
Yellow warnings for rain have also been enforced for Wales, the west Midlands, east Midlands and east of England.
The Met Office confirmed it has been the wettest December and January combined for more than 100 years, with rain falling on 23 out of 31 days in January across the UK.
There was 183.8mm of rainfall in January, 51% higher than the average. Between mid-December and the end of January, southern England was deluged with over five months' worth of rainfall, figures show.
Met Office spokeswoman Laura Young warned there is no reprieve in sight, with more rain set to batter the UK in coming days.
"There is this deep depression that is going to bring a further 20mm to 40mm of rain tonight to the south west, the south east coast and south Wales," she said.
"Locally you could see 10mm to 20mm falling within a two to three hour period over Somerset and Dorset during tonight."
The weather should abate tomorrow morning, before the whole of the UK is "engulfed" by heavy rain overnight on Friday, she said.
"We are looking at another 10mm to 20mm widespread, it will be heaviest across southern England," she said. "Locally in the area within the amber warning you could see 30mm so it will lead to further flooding, unfortunately."
Severe winds are expected across the UK on Saturday, with some areas of exposed coastline potentially seeing gusts of wind of more than 80mph.
Earlier, Communities Secretary Eric Pickles said that the Government would provide £130 million for emergency repairs and maintenance.
Mr Pickles, standing in for Environment Secretary Owen Paterson, who was undergoing emergency eye surgery on his retina, told the Commons that the severe weather had caused damage to the transport network and sea defences as well as power lines.
Homes in flood-hit areas have been evacuated and gusts of winds and storms have destroyed a stretch of railway track in Dawlish, Devon. Around 5,000 properties have been affected by flooding across the country, including 40 in Somerset.
A huge pumping operation is still taking place on the Somerset Levels, with up to 2.9 million tonnes of water being pumped off the Levels every day - the equivalent to three Wembley Stadiums.
Mr Pickles said Prime Minister David Cameron would chair a meeting of the Government's Cobra emergency committee today.
The Prime Minister's official spokesman said Network Rail were in discussions with the Ministry of Defence to determined whether the Armed Forces were able to provide assistance with disruption to railway services.
Asked whether this could mean the Army being sent in to help mend the track at Dawlish, the spokesman said: "The Prime Minister has said that he is ruling nothing out in terms of providing assistance."
During a visit to Birmingham, Mr Cameron insisted he would visit Somerset himself "when the time is right" but insisted his top priority was co-ordinating the Government's response to the floods.
He said: "Well, I made a flood visit after Christmas and I'll be visiting Somerset of course when the time is right but what matters most of all as Prime Minister is that the whole of the Government is working towards helping with this problem.
"That's why I chaired a Cobra yesterday, why I announced £100 million of funding for the Environment Agency and why we're looking at everything that can be done to drain the water including getting all of the pumps out of the DCLG and down to Somerset.
"When it's right for me to visit I'll be there don't worry. I think it's absolutely vital. We've had ministerial visits in the past and there'll be more to come but the most important thing right now is to co-ordinate all the effort for people in Somerset."
However, Labour leader Ed Miliband accused the Government of "slack" planning and a "slow" response to the flooding.
"I think the priority now is to get all of the help possible to those who have been affected by the flooding and the storms," Mr Miliband said.
"The Government has got to do what the Prime Minister promised they would do by the end of January, which is to review all of the investment there is in flood protection to see whether it's adequate and to learn lessons about why the response has been so slow, particularly in parts of Somerset which have been under water for six weeks now."
Details of Lord Smith's visit to Somerset tomorrow have not yet been released.
David Cameron tweeted: "I 've just chaired a COBRA on the floods. I welcomed the Marines going to Somerset. All Govt depts doing all they can to help those affected."
Mr Cameron said he wanted to reassure people affected by the floods that the Government was keeping up its "urgent response".
He said: " I have chaired another Cobra meeting this evening to ensure we continue to do everything possible to help communities affected by these storms.
"Today, Royal Marine commandos from Taunton have been deployed in Somerset to fill sandbags and provide relief to the local emergency services, as more bad weather is forecast.
"The Environment Agency has ordered specialist pumping equipment to clear roads, in addition to the extra pumps we have already sent, and they will keep looking at all options for pumping and dredging.
"In Dawlish, National Rail is undertaking a full inspection of the railway line and working with Army engineers on options to shore up the damaged section: a regular rail replacement service is now in place.
"Across the country another £30 million will be spent on urgent flood defence repairs this year, on top of the £100 million next year which I announced yesterday.
"I want to reassure everyone affected by these terrible storms that we will continue to keep up our urgent response and help get them back on the move."