Thousands more homes in the South East could be inundated by floodwater after communities along the Thames were warned river levels will continue to rise over the coming days.

Hundreds of properties in Berkshire and Surrey have already been flooded after the river reached record levels in some areas.

Thames Valley Police has declared a “major incident” in East Berkshire after the river burst its banks in several areas.

Prime Minister David Cameron will today continue his tour of flood-hit areas, as he tries to calm concerns the Government has lost control of the crisis.

There are 14 severe flood warnings, meaning an imminent danger to life, in place between Datchet and Shepperton Green, while two others remain in Somerset.

More than 300 other flood warnings and alerts have also been issued, including in the South East, South West and the Midlands.

The Thames barrier was also closed overnight in order to protect communities west of London.

Commuters are expected to suffer delays on train networks in the South today, with services into and out of Paddington station particularly affected.

Passengers have been advised to check services before attempting to travel this morning.

A statement from First Great Western said: “Network Rail has informed us that signal and safety equipment in the Maidenhead area has been affected by flooding.

“This means we are only able to run trains on two of the four tracks into and out of Paddington.

“Services are still running but at a significantly reduced frequency, and customers should expect delays and cancellations to services.”

In Datchet, where the military put down a 600-metre-long sandbag wall, residents have been hit by flooding after the water rose by over half a metre in 24 hours, blocking roads and train tracks.

Residents and shop owners waited for sandbags to protect their properties and deliveries were quickly carried away.

Local businesswoman Isabel Gil said: “I would have thought there would be a lot of sandbags all prepared in advance for this situation but they seem like gold dust. I can’t get hold of any.”

Much of the nearby village of Wraysbury was also under water. Police said they would join boat patrols with fire and rescue personnel overnight.

Around 200 Royal Navy personnel were filling sandbags in Chievely, near Newbury, for distribution along the Thames Valley.

Eighty are transporting those sandbags and building defences in Staines and Chertsey, where the water is the highest it has been in over a decade.

The Environment Agency told Sky News at least 400 homes had flooded since Sunday in the South East and 4,000 more were at risk.

On a visit to Chesil Beach on Monday, Mr Cameron praised the work of the Environment Agency but gave only limited support to its chairman Lord Smith.

“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.

“There will be time later on for talking about such things.”

Communities Secretary Eric Pickles told MPs there was a high risk the River Severn and River Wye would also break their banks.

Speaking later, after chairing a COBRA meeting, he said: “As we continue to face these extraordinary weather events, I want to make clear again this evening that work is being done to identify and prioritise any sites where we may experience problems in the coming days.

“I want to reassure the public that their safety remains our first priority. We are doing everything possible to protect people’s homes and communities.

“In addition, strategic sites such as water and electrical plants are being given special attention to ensure that homes are not left without vital resources.”

Paul Leinster, chief executive of Environment Agency, said: “Extreme weather will continue to threaten communities this week, with further severe flooding expected Monday evening into Tuesday along the Thames in Berkshire and Surrey.

“River levels are high across south west, central and southern England and further rain has the potential to cause significant flooding.”

As far down river as Kingston on the outskirts of London the river is high and rising.

Residents have been evacuated in several areas, including in Walton-on-Thames, Surrey, but some people are refusing to leave as they are worried about possible looting.

The Met Office has issued a yellow weather warning for further spells of rain, sometimes heavy, and strong winds overnight into Tuesday morning for southern England.

It said: “The public should be aware of the risk of further disruption due to flooding.”