Overrunning engineering work at the UK’s busiest railway station has caused major rush hour disruption.
No South Western Railway (SWR) trains were able to serve London Waterloo from 5am on Friday because of a power supply issue.
All lines were reopened two hours later, but delays and cancellations were expected to continue until 2pm as some trains were unable to leave depots until the problem was fixed.
Around 260,000 people travel through London Waterloo every day.
The engineering work was being carried out by Network Rail.
A spokeswoman for the public sector company said: “We apologise to passengers for the disruption to services across the South Western network this morning owing to multiple possession overruns as a result of a power supply issue.
“Disruption, including severe delays and cancellations, will last until the afternoon.
“Passengers should check with their train operator or visit www.nationalrail.co.uk before travelling.”
A separate fault with the signalling system at Milton Keynes Central resulted in some lines through the station being blocked on Friday.
This affected Virgin Trains, London Northwestern Railway, Southern and Caledonian Sleeper services.
Virgin Trains was unable to operate any departures from London Euston due to the issue.
Passengers were encouraged to use alternative routes and were warned that journey times could be extended by up to one-and-a-half hours.
A normal service was expected to resume at 11am.