As the snow melted across south London and Surrey, travel routes and local services were slowly getting back to normal.

Drivers were being warned of ice on the roads. By the morning rush hour on Wednesday snow and ice were still causing delays on the M25 in Surrey and on the A3.

Southern Railway cancelled more than 20 services on Wednesday morning because some trains were out of place following the snow disruption.

Nevertheless the rail company said it would be running a normal timetable. A Southern spokeswoman said: "We are working hard to restore as many services as possible."

South West Trains, which operated a reduced service on Tuesday, said on its website it was aiming to run a normal weekday service on Wednesday. “However, this is subject to icy weather conditions,” the statement added.

The south London tram network resumed a full service late on Tuesday afternoon as the last snow was cleared off the tracks.

Buses have also running a normal service by Wednesday morning. London’s entire bus fleet was suspended on Monday because more than 20 slid off the roads during heavy snowfalls the previous night, said London’s transport commissioner Peter Hendy.

He apologised for the disruption: "It was the worst snowfall for two decades.

"The local authorities deployed everything they had on Sunday night and Monday morning, but it just wasn't enough for the circumstances."

Both runways at Heathrow have reopened on Tuesday, although some flight delays persisted. On Monday snow caused almost 800 flight cancellations at the airport.

Heathrow, Gatwick and City Airport all expected a normal service on Wednesday.

Most state schools across south London were reopening on Wednesday after pupils enjoyed two days of playing in the snow.

Hospitals were resuming planned surgery and outpatient appointments on Wednesday.

However, a spokesman for Mayday hospital said: “We would still advise anyone who does not need the urgent and specialised services provided by a hospital to stay away until the weather improves further.”

This week’s blizzards caused Britain’s heaviest snow in 18 years. The last time the country saw such weather was in 1991, when central London had 15cm of snow.

On Monday Epsom had the deepest snow across the whole of Britain, with 12 inches (31cm) measured in some places.