Several London Underground lines as well as the Overground are experiencing delays, suspensions and reduced services.
A signal failure caused the entire Circle line to be suspended earlier this morning – but now the line is riddled with severe delays due to a broken-down train.
Other key commuter lines the District and Hammersmith & City line are seeing severe delays – True Tube Status, a motoring app, says journeys are about 40% and 20% longer than usual respectively.
The Overground is severely held up between Willesden Junction and Clapham Junction, while train cancellations between Moor Park and Chesham are giving Metropolitan line riders quite the headache.