Thousands of travellers faced delays on their way to work today, after a dusting of snow disrupted rail services in the south of England.
Flights out of Heathrow and Gatwick airports were also affected, while motorists faced difficult driving conditions on the roads and a series of weather-related signal failures caused severe disruption to the London Underground.
A band of snow moved south overnight leaving a covering of up to two centimetres in some areas.
Southeastern, which operates rail services into London from Kent and Sussex, said that a failed train in the Bickley area was having a knock-on effect on services into Victoria and Blackfriars from south-east London.
"Delays, hopefully many of them small, could affect thousands of people this morning because in south-east London services are fairly frequent so any small delays could have a knock-on effect," a spokeswoman said.
But she added that services from the coast and Kent mainline areas were running "fairly well" while a handful of points failures were also being rectified.
South West Trains, which runs between the capital and the south and south-west, reported 15 separate points failures including at key hubs such as Waterloo, Clapham Junction and Wimbledon, as well as St Margaret's and Guildford, Surrey.
A spokeswoman said that disruption was most acute in the London area and the immediate surroundings.
Around 80% of the company's services pass in or out of Waterloo during the day, she added. The company's website also listed "poor weather conditions" as a reason for cancellations of services between Lymington and Brockenhurst in Hampshire.
The rail disruption was compounded by a series of signal failures on the London Underground network. Services on the Central, Bakerloo, District, Circle, Hammersmith and City, Jubilee, Metropolitan, Northern, Piccadilly and Victoria lines were disrupted, causing congestion and forcing many passengers on to buses.
A London Underground spokesperson said problems on the Tube were due in part to poor planning and execution of maintenance by Metronet. "Cold weather and a threat of snow were forecast and Metronet chose not to undertake the necessary prevention work overnight. This includes running special trains to clear snow and ice from tracks and junctions and having extra technical staff available," they said.
“Metronet chose to carry on with regular engineering work. This failure to deal with the forecast cold weather led directly to much of the problems on the Tube this morning."
Several bus routes have also been withdrawn or diverted because of conditions on the roads. The worst affected areas are New Addington and Croydon in south-east London. Transport for London has advised that the Croydon tramlink is accepting bus tickets.
Affected routes include numbers 64, 130, 314, 363, T31 and T32 in New Addington and Croydon routes 64, 75, 194, 198, 250, 367, 409 410, T33 and X26 which are all on diversion.
In East and West Sussex, police were urging motorists only to venture out if making essential journeys.
A Sussex Police spokeswoman said they had received 74 weather-related calls this morning, including a car careering into a gas main in Buxted High Street.
British Airways cancelled 16 short-haul flights from London airports because of the weather conditions.
Worst hit was Heathrow where 13 services were cancelled, with a further three at Gatwick, a spokeswoman said.
"We have got delays of about 30 minutes at Heathrow at the moment and up to an hour at Gatwick," she said.
A spokesman for Heathrow Airport said the problems were believed to relate to de-icing.
"We have had a few cancellations from British Airways this morning but our runways are operating as per normal, all the snow has been cleared," he said.
He added that passengers had experienced delays getting to the airport by road.
A spokesman for the Highways Agency said: "The Highways Agency's gritter fleet has been out in the night and the agency will continue to monitor conditions throughout the day as further snow is forecast mostly down the east coast of England.
