London Transport said they were able to run between 60% and 70% of trains in the morning rush hour, a figure disputed by the Rail, Maritime and Transport union.

Clash over the level of service

"Management have misled their staff throughout this dispute and they are at it again, grossly exaggerating the number of trains running," said Bob Crow, the RMT's Assistant General Secretary.

The union claims that up to 6,000 of their members have joined the strike.

By mid afternoon there was a mixed picture across the tube lines:

• There are no services on the Waterloo & City and Circle Lines.

• Normal service on the Metropolitan Line.

• 95% service on the Jubilee Line.

• 88% service on the Bakerloo line.

• No Olympia service on District Line but 79% service for the remainder of the line.

• 75% service on the East London Line.

• 60% service was running on Victoria Line

• 51% service was running on Northern Line

• 43% service was running on Central Line

• 39% service was running on Piccadilly Line

• 27% service was running on Hammersmith & City Line

Half of London Underground's train drivers are RMT members along with most station staff. The union is seeking assurances over job security and conditions if parts of the system are privatised.

The RMT has also called a four-day strike of maintenance staff on the mainline railway network on Friday.

'Cycle wherever feasible'

The Transport minister Glenda Jackson has urged commuters not to drive into London on Monday and Tuesday.

She said employers should encourage staff to work from home, stagger working hours or arrange alternative transport.

"I would encourage people to walk or cycle wherever feasible," she added.

Commuters in London can get the latest travel news on BBC GLR, the local radio station for London, broadcasting on 94.9 FM.