Train services across South London are being delayed due to a train fault.
The London Bridge to Victoria route is being delayed, with the service starting from Balham more than half an hour late.
A tweet from Southern Rail UK said: "INFO: 07:53 London Bridge to London Victoria will be started from Balham at 08:25 due to a train fault."
Frustrated commuters have been venting their anger on social networking websites.
Jonathan Byrant wrote: "Morning @SouthernRailUK. 8:25 Streatham hill to Sutton back to eight minutes late again so I'll miss my connection at crystal palace yet again.
"I see the claim today is over running engineering works. @SouthernRailUK pants on fire methinks."