LONDON - London Tube staff on the District Line on Friday began a 24-hour strike amid a row over the treatment of a train driver who allegedly went through three red lights, sending thousands of commuters into rush-hour travel chaos in the morning.

Passengers reported "nightmare" crowds on District Line platforms as a result of the strike. Transport for London (TfL), the city's administrator of traffic and communications, said that 40 of the line's 70 trains were running on Friday morning, with all stations being served.

Problems were worst on services to the outlying western and eastern branches of the line, which is used by more than 800,000 passengers a day.

The industrial action was sparked by union anger at the way managers dealt with a new driver who alleged passed three signals in 11 weeks, two of which are said to have been passed "at danger."

The driver is said to have agreed to being "redeployed" to a role on a station, but union Aslef dispute this.

The District Line is the fifth largest across the Tube network and serves 226 million passengers a year.