The cold weather meant more misery for rail travellers today with serious disruption on a number of key commuter routes.
Some south-east train companies were hit by a build-up of ice on the "third rail" from which trains get their power.
Services in Hampshire, Surrey and Kent were particularly affected, with a number of trains being delayed and cancelled.
There were also problems on the Tube where late-running engineering work meant a closure of a large section of the Metropolitan line at the start of the rush hour.
Services did resume later, but with severe delays.
On the main line in Kent, the third rail problem meant there were delays of up to 50 minutes to trains between Sevenoaks and Orpington, while trains were unable to run between Havant in Hampshire and Guildford in Surrey.
There were chaotic scenes at stations including Guildford, with little information and confusion among passengers.
Some gave up waiting for a train and went home or took to their car to complete their journey.
It was the latest in a series of problems to hit rail services in the area in recent weeks.
The third rail difficulties also meant delays for passengers travelling between Reading and Wokingham in Berkshire and there were no services between Alton in Hampshire and Farnham in Surrey and delays between East Grinstead in West Sussex and Oxted in Surrey.
The problem also led to delays of up to 45 minutes for passengers travelling between Horsham and Three Bridges in West Sussex, while similar-length hold-ups were hitting services between Tonbridge in Kent and Redhill in Surrey.