Passengers on the District Line saw a reduced service on Friday following a strike by Tube drivers.
Members of Aslef, based at the District Line's Acton Town depot, have walked out for 24 hours regarding a dispute over the treatment of a driver involved in a number of safety incidents who has now been "reassigned" to a station staff job.
The driver in question is alleged to have gone through three red lights in 11 weeks of driving, two are through to have been passed at danger within a four-week period.
It is expected that there will be delays throughout Friday, according to Transport for London (TfL).
The District Line drivers have gone on strike.Credit: PA
Nigel Holness, London Underground's (LU) director of network operations, said: "The safety of our customers and our staff is our top priority.
"In this case, a driver was offered an alternative role on our stations following a number of safety incidents in their first few months of driving.
"With so many incidents in a short space of time, despite several weeks of training and assistance, it was simply not safe for this employee to continue in a role as a driver.
"The situation is not as the union has described as no disciplinary action has been taken against the employee and our action is in line with the safety policies agreed with our trade unions."
Finn Brennan, of Aslef, said: "Instead of recognising the concerns of our members, and reps, LU management are refusing to acknowledge that they have failed to follow their own procedures, threatened a disciplinary hearing to make a driver 'agree' to be redeployed, and now refuse to talk to this union."
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