A strike by station staff on London's Tube network over the New Year period has had "little impact", London Underground bosses said.
The strike's full effects may not be felt until early evening
Of the 275 stations, up to 37 stations closed due to a lack of staff and Northern Line services were delayed, Transport for London (TfL) said.
Rail Maritime and Transport (RMT) union members were protesting at new rotas.
Up to 200,000 people saw in the New Year in central London, police said. The strike continues until noon.
British Transport Police said the evening had passed "very well indeed" with no reports of overcrowding.
The dispute involves station staff, not train drivers, so most lines were running without delays, but some trains were unable to make their usual stops because of closed stations.
Most of the stations that closed were outside the central area, and other stations further out and above ground were left unstaffed with their ticket barriers open.
Zone one stations affected by the strike included Covent Garden, which was closed, and King's Cross where Victoria, Piccadilly and Northern Lines were not stopping.
Extra buses helped ferry people home after the festivities in central London, which included a 10-minute firework display on the Thames and celebrations in Trafalgar and Parliament squares.
The strike, scheduled to end at noon on New Year's Day, is also expected to affect London's New Year Parade, due to start at noon.
One of the organisers, Dan Kirkby, urged people to come in despite the strike: "We are calling upon London to really get off its backside and come and make this event a really superb success, which it deserves to be."
The dispute centres around a rota linked to the introduction of a new 35-hour week for Tube workers.
The RMT said that when it agreed to make the change it had not been shown new work patterns, which it believes will compromise safety for staff and travellers.
More strikes planned
RMT leader Bob Crow told the BBC he had offered to suspend the strike, in return for LU suspending the new rotas, but LU had refused.
He added: "We've had to try and put maximum pressure on London Underground to concentrate their minds.
"And if New Year's Eve won't concentrate their minds we're going to have to look in the new year to stepping up the action."
The RMT plans more strikes later this month.