Rush-hour commuters on the District and Circle lines endured yet another morning of travel misery caused by a signal failure.
Transport for London warned travellers faced long delays between Barking and Upminster because of a signalling fault at Westminster. There was also no service anti-clockwise on the Circle line.
TfL tweeted the problems were reported soon after 6am.
Just after 8.20am the disruption was downgraded to minor delays.
A TfL spokesman said: "We apologise for the disruption caused to our customers using the Circle and District lines this morning.
"This was caused by a signal failure at Westminster at 6:20am.
"Our engineers have fixed the problem and we’re working hard to get a good service running as quickly as possible."
"Work is underway to modernise the signalling on the Circle and District lines and when completed it will mean improved reliability and more trains during peak periods."
It comes the day after part of the line was suspended for several hours because after a train derailed at Ealing Broadway.
It comes a day after part of the District line was suspended for several hours after a train derailed at Ealing Broadway.
On Tuesday, commuters were also hit with delays when the Circle line as completely suspended because of a signal failure at Baker Street.
Passengers on the District, Circle, Metropolitan and Hammersmith and City line were all affected during the brief shut-down.
