A faulty train sparked commuter chaos this morning as the Jubilee and Metropolitan tube lines faced severe delays due to the issue.
Passengers across the network were blighted by packed carriages and platforms.
At Wembley Park, which is served by both lines, huge crowds formed as passengers were met with a stunted service.
Some of those affected attempted going to Wembley Central, where sprawling queues formed.
The platform at Harrow on the Hill was jam-packed with commuters as trains were terminated.
In regards to the Jubilee Line, a Transport for London statement said: "Due to an earlier faulty train at Neasden. London Underground tickets are being accepted on local bus services."
With the Metropolitan Line, there was no service between Baker Street and Aldgate due to the fault.
Tickets were being accepted on London buses and by Chiltern Railways, Transport for London said.
The faulty train has been cleared but issues have persisted.
Nick Dent, director of line operations at London Underground, said: "We are sorry for the disruption Jubilee and Metropolitan line customers experienced this morning and will be refunding all customers affected. A Jubilee line train became faulty in the area where it shares track with the Metropolitan line, affecting both routes. Our response teams have moved the faulty train and we are working hard to restore a normal service.”
There were also issues on the overground, with no services between South Tottenham and Barking.
Meanwhile, damage to overhead electric wires is causing severe disruption to train services between Bedford and London St Pancras.
The problem, near Luton, has blocked two of the four lines on the route, resulting in commuters using Thameslink and East Midlands Railway being hit by delays and cancellations.
Network Rail engineers are working to repair the wires but disruption is expected until the end of service on Thursday.
