Snow that caused havoc on rail and roads today is likely to bring commuter chaos for the rest of the week.

More than four inches of snow fell in areas east of London, delaying trains from Kent, Sussex and Essex.

Many London roads were gridlocked as rail commuters turned to their cars, fearing that public transport would fail. Long queues formed on the M25 north east of the capital and Finchley as snow came down.

Transport for London (TfL) urged Londoners to only travel when "absolutely necessary".

For the second day in a row the Met-office issued a severe weather warning for South-East England. Sub-zero temperatures and more snow, one to three inches (3 to 7cm) deep in some places, can disrupt transport until Thursday.

Wednesday night could see heavier showers as the wind, which blows in the bad weather from the North Sea, is expected to pick up further, said a Met office spokesman.

The cold snap is attributed to high pressures over Scandinavia and Northern Europe colliding with low pressures west of the UK.

This morning South Eastern passengers on the Hastings line into Charing Cross and Cannon Street were delayed for up to an hour. Even though de-icing trains have been running all night, some services were cancelled.

Local and long distance commuters on Southern Railways also suffered delays of up to half an hour.

A National Rail spokesman said the bad weather caused "some delays" in the capital.

Every night this week hundreds of railway workers, or "snowmen", will clear snow off the tracks. From 5pm de-icing trains spread a special solution on the conductor rails. Once services stop overnight, empty passenger trains drive around the network to keep the network free from ice.

An army of 35 TfL gritters have been out on main roads in London since 2pm yesterday. They use 3,800 tonnes of salt from five depots to prevent ice from forming on road surfaces.

Sainsbury's Bank car insurance warned motorists against the growing car theft called "frosting". Up to 135,000 cars have been stolen over the past five years when owners left them unattended whilst the engines were warming up.

The Highways Agency advised motorists to be prepared with a "winter weather kit", including warm clothes, a hot drink, de-icer, a torch and a spade. They should check weather forecasts before they set out, and delay their journeys if necessary.