Media playback is unsupported on your device Media caption The railway line in Dawlish is hanging in mid-air, as Jon Kay reports

Parts of Britain have been hit by a storm which destroyed a stretch of railway, forced people from their homes and left thousands without power.

A section of the sea wall in Dawlish, Devon, collapsed and left the railway to Cornwall suspended in mid-air.

Residents of homes on the Somerset Levels were evacuated amid fears flood defences could be overwhelmed.

David Cameron chaired his first Cobra meeting this year and announced an extra £100m for flood works.

At Prime Minister's Questions he pledged £75m for repairs over the next year, £10m for urgent work in Somerset - where several rivers have flooded - and £15m for maintenance.

David Cameron knows he cannot afford people in the countryside to think he simply doesn't get it

Mr Cameron said he would "ensure that everything that can be done to get stricken communities moving is being done: there are no restrictions on help".

The BBC's political editor Nick Robinson said Mr Cameron had given the "clearest possible sign" that he needed to "be seen to be getting a grip" on the response to the floods.

Environment Secretary Owen Paterson's handling of the crisis has been widely criticised.

He will not be chairing the Cobra emergency committee or giving a statement to the House of Commons on Thursday after being diagnosed with a detached retina. Instead, Mr Paterson will undergo emergency surgery.

Media playback is unsupported on your device Media caption BBC weather presenter Matt Taylor predicts more rain and strong winds throughout February

At the scene Seldom can one small village have been so inundated by officials and their vehicles. In Moorland, on the Somerset Levels, floodwater has reached people's gardens, and there is a huge effort to save properties as residents are advised to leave. Environment Agency workers, at the centre of a political as well as meteorological storm, are here in huge numbers. Monster pipes are being laid across a road to shift great volumes of water from an overwhelmed drainage canal into the River Parrett. It is an effort to bypass Moorland and save the village. Despite the advice to leave, announced from a police helicopter - as in a Hollywood disaster movie - many people, if not most, are staying to look after their homes. One woman told me she was worried about looters. Residents have an anxious wait to see what the water does. For many on the Somerset Levels, it's an anxiety present since Christmas.

Western Power Distribution said about 44,000 customers had been affected by power cuts since Tuesday afternoon.

By 22:00 GMT on Wednesday, thousands of homes had been reconnected but 953 customers remained without power across the South West. In Cornwall, 490 were still cut off.

On the Somerset Levels, police used a helicopter to advise the occupants of more than 150 properties in Fordgate and Northmoor to leave their homes.

Forecasters say there will be an "improving picture" on Wednesday evening. But there will be rain moving up from the south coast on Thursday morning which will spread to south-west England in late morning. About 20-30mm of rain is expected throughout the day.

More heavy rain and gales are forecast for Friday night into Saturday.

Dawlish resident Robert Parker said the storm was "like the end of the world".

He said: "It was like an earthquake. I've never experienced anything like it. I've been in some terrible storms in the North Sea, but last night was just a force of nature."

Image copyright AP Image caption A section of rail track dangles over the sea after the wall collapsed at Dawlish

Image copyright PA Image caption Waves continued to lash the seafront

First Great Western said all lines between Exeter St Davids and Plymouth were closed because of the collapsed track at Dawlish and the bad weather.

Limited services are running between Plymouth and Penzance, with rail replacement services due to be provided from Thursday.

Network Rail has estimated the damage at Dawlish could take at least six weeks to fix. First Great Western said the repairs could not begin until the weather improved.

Speaking after the Cobra meeting, the prime minister said he was "determined to ensure a proper alternative service" was provided while the railway line at Dawlish remained out of use, with a solution found to fix it as soon as possible.

The Environment Agency has two severe flood warnings in place in south-west England - meaning there is a danger to life - down from a high of nine earlier on Wednesday.

It has also issued about 60 flood warnings and more than 200 flood alerts.

The Scottish Environment Protection Agency has issued five flood warnings and several flood alerts.

The Met Office has issued an amber severe weather warning for rain - meaning "be prepared"- from 15:00 GMT on Thursday until 23:00 GMT on Saturday across southern England.

Media playback is unsupported on your device Media caption "This is the police helicopter, the flood danger is imminent, evacuate"

In other developments:

Firefighters have also been called out to deal with dangerous structures. There have been two incidents in the Tenby area of Pembrokeshire with roofing being blown off buildings.