Up to three million Londoners had their journey into work disrupted by strike action on the tube.

The strike was called by the Rail, Maritime and Transport union after they failed to resolve a dispute with London Underground (LU) management.

The conflict centres around levels of pay and the number of hours tube drivers are expected to work.

Picket lines were erected outside several underground stations and the RMT said that the action was "solidly supported" by members.

Union leaders have not ruled out more strikes in the future if further talks fail to break the deadlock.

LU has described the strike as "unnecessary". It said the action had made travel in London "incredibly difficult" for millions of people.

Industrial action began at 6.30pm on Tuesday. Services resumed at 6.30pm on Wednesday but were not running smoothly until Thursday morning.

Many chose to drive into the Capital, despite warnings of gridlock and the mayor's decision not to suspend the congestion charge.

This caused severe congestion on roads into central London and increased journey times for buses, which were packed with commuters during peak times.

The AA said that the main routes around London were "noticeably busier".

The strike came as Transport for London stepped up its calls for the government to deliver more investment in the Capital's transport services.

"The growth in London's population makes immediate and sustained improvements in the transport network essential," said transport commissioner Bob Kiley in an open letter.

"Since 1989, London has been the fastest-growing major city in Europe, adding half a million people in the past 15 years.

"In little more than a decade, another 800,000 people are expected to live here, raising demand for all forms of public transport by 38 per cent of current levels."