Video: Just when you thought spring was in the air... back comes the snow

While motorists suffered a series of accidents on major routes, train passengers had to cope with delays caused by a series of overruns of weekend engineering work.

Paul Knightley, a forecaster with MeteoGroup, the weather division of the Press Association, said: "It's been a rotten start to the week - cold, dark, wet and windy."

Snow fell today in large parts of southern England, with Gloucestershire, Oxfordshire, Buckinghamshire and Suffolk all affected.

In Aberdeenshire, temperatures fell as low as minus 18C (around 0F) last night.

On the roads, a section of the A1 in Northumberland was closed because of an accident, while a vehicle fire shut part of the M54 in Shropshire.

On the railways, buses had to replace trains on East Midlands Trains' services between Boston and Grantham in Lincolnshire because of over-running weekend engineering work.

Overruns also led to delays to train services in the Oxford area, as well as delays on East Coast services through Hitchin in Hertfordshire and on First TransPennine Express services, where buses had to replace trains between Scunthorpe and Cleethorpes.

Mr Knightley said: "Snow could drift into East Anglia later today and there's likely to be a sharp frost in many places tomorrow.

"Tuesday could also see sleet and snow in parts of Wales, the north Midlands and the Peak District."

He went on: "The rest of the week could see a battle between the moist air and the cold air. There could be a lot of rain and a lot of snow."

This winter could be the coldest since 1978/79, with final confirmation of where 2009/10 stands in the record books due at the end of this month.

Mr Knightley said: "This winter has certainly been a cold one in Britain and in many parts of the northern hemisphere.

"Yet records show that - globally - January was the hottest month ever."

Sudden heavy snow in Bedfordshire around 8.30am led to Luton airport closing the runway.

A number of flights, including some by low-fare operator easyJet, had to be cancelled.

A spokeswoman for the airport said: "The snow came down very heavily for around an hour and it was decided that the runway would have to be closed so it could be cleared."

It was hoped the runway would reopen again around 1pm, but passengers were warned to expect delays and cancellations.

The East of England Ambulance Service said that with more snow showers expected to fall people should think before contacting emergency services.

"We rely on the public's good sense to use the 999 service wisely," said associate director of emergency operations Neil Storey.

"If you need advice but don't have a serious or life threatening condition, consider the other options available to you such as calling NHS Direct on 0845 46 47 or contacting your local GP or pharmacist."

Mr Storey also warned road users to drive safely and to only make journeys if necessary.

He added: "While the snow and icy conditions continue to present a hazard, particularly on smaller roads and side streets which don't always benefit from gritting or salting, motorists should remain particularly careful."