Millions of commuters jammed buses, rented bicycles or simply walked for miles on Thursday as a 24-hour strike closed the British capital's subway system and threw public transportation into chaos.

Train drivers on the London Underground solidly supported the strike in a dispute over pay and schedules that are due to take effect when a 24-hour service is introduced on some lines later in the year.

The high level of support made the effects of the strike more severe than previous ones, in which management was able to keep a few Tube lines operating.

Business groups said the strike will cost London tens of millions of pounds in lost productivity.

"I have to file a statement for today-I don't know how I am going to do it. I am utterly fed up," said distraught attorney Susan Miller, 48. "I just don't think (the strikers) have seen the big picture here."

London's subway system, with 4 million journeys a day, normally shuts down between midnight and 1 am, with the overnight shift reserved for track maintenance. While it has operated all night on New Year's Eve, the move to have some lines running 24 hours on weekends marks a huge shift for the 152-year-old system.

London Underground Managing Director Mike Brown apologized for the disruption, but insisted it was a "remarkably fair" pay offer.

"This strike is unnecessary," he said.

Transportation officials said the offer includes a 2 percent pay rise, a 500 pound ($770) night Tube launch bonus and an additional 2,000 pound bonus for night drivers. Unions said management is trying to bulldoze in new work patterns that will cause stress and wreck the work/life balance of people in critical safety jobs.

"We've wasted three months in negotiations that failed to address staff concerns," said Mick Cash, the RMT union's general secretary.

Zhang Chunyan in London contributed to this story.