Travellers are being warned to prepare for difficult conditions on road and rail tomorrow.

The Highways Agency has advised motorists to check the weather forecast this evening and allow extra time for their journey in the morning.

Steve Crosthwaite, head of the agency's national traffic operations centre, said: "During periods of severe weather we also suggest people consider whether their journey is essential.

"They may want to delay their travel until conditions improve and to allow our winter fleet the chance to treat the roads."

The agency, which looks after motorways and major A roads in England, has a 500-strong fleet of salt spreaders and snow ploughs available.

Mr Crosthwaite added: "We are using salt to treat the road network and have ploughs and snow blowers on standby if necessary.

"Our traffic officers are working around the clock to monitor our road network, deal with any incidents and keep traffic moving."

South West Trains said it would be operating a revised timetable on a number of routes tomorrow. These include London to Bournemouth and Weymouth, London to Salisbury and Portsmouth and London to Reading.

East Coast train company is lifting ticket restrictions for all journeys on its trains which arrive in, or depart from, King's Cross station in London after 10am tomorrow.

They have advised passengers wherever possible to travel before 6pm tomorrow, as heavier snowfalls were predicted after that time.

The Southeastern train company also advised passengers to make checks before setting out.

A Southeastern spokesman said: "Given the weather forecast, there may be disruption on some routes through the day."