Commuters trying to get to work from West London faced a chaotic start to the day because of severe delays on the Piccadilly Line.
The line was suffering from issues as far as Acton Town to Uxbridge this morning, because of a signalling failure at South Harrow, Transport for London said.
Although it said there was a good service on the rest of the line, passengers complained that it was in "meltdown".
In addition, the Waterloo and City line was suffering from delays because of a faulty line.
And commuters also complained that the Central Line was suffering delays, although there was nothing official from TfL.
@TfL 20 mins for a train into london on the cental line during rush hour? Care to share the crack you're smoking?— Bill (@Ill_Bill_90) March 17, 2016
There was no word on when the Tube network would be back up and running as normal.
More to follow...