Commuters have faced long delays after a Tube strike over ticket office closures took effect in London. Members of the Rail, Maritime and Transport union mounted picket lines outside stations after walking out at 9pm last night.

The action will last for 48-hours and will be followed by a three-day stoppage next week. Large queues built up as early rush-hour passengers waited until 7am this morning for the first Tube trains to run.

London Underground said it was running services on nine lines despite the "pointless" strike. There were almost 8,000 buses on the roads - the most ever operated in London - after an extra 266 were put into service.

London Underground managing director Mike Brown said "Thousands of staff and volunteers are working hard this morning to keep London working and our customers informed in the face of this pointless strike. More London Underground staff have come to work this morning than during the strike back in February, and a record number of London buses are operating".

At Euston station in north London this morning, customers crowded around the entrance to the Underground, waiting for the clock to tick round to 7am.

On the busy Victoria line, where trains normally run every two minutes or so, there was only a 10-minute service when trains finally began running. And at Clapham Junction, there were large crowds as more passengers chose to take overground services and some platforms were restricted.

At London's Victoria station, passengers pouring off mainline trains were confronted with a wall of people waiting for Tube services.

Heathrow Express said trains between Paddington and Heathrow were running as scheduled due to staff reserves.

Opposition to closure plans

The RMT union is embroiled in a fresh row over the ticket office closure plans, which officials warn threaten safety as well as almost 1,000 jobs. London Underground denied there would be any impact on safety and said ticket office staff would provide a better service if they were moved to other parts of stations.

The RMT said its members were solidly supporting the industrial action, as the union again attacked London Mayor Boris Johnson over the future of ticket offices.

RMT acting General-Secretary Mick Cash said "London Underground have dug themselves into an entrenched position and have refused to move one inch from their stance of closing every ticket office. It is scandalous that Transport for London are blowing what we estimate to be hundreds of thousands of pounds on politically-motivated adverts and propaganda designed to deflect attention from Boris Johnson's broken promises."

Business groups warned that the strikes will cost the London economy millions of pounds.

Mr. Brown said "The RMT leadership appear to remain implacably opposed to the modernisation of the Tube that will radically improve customer service and help us keep fares down".