Travellers have reported being told to evacuate Clapham Junction station in the last half an hour.
The alarm was raised at the station, with a loud siren sounding, but was soon called off after it emerged it was a false alarm.
A spokeswoman for South West Trains said: "It appears that there is a small technical fault with one of the alarms on a platform.
"It is being rectified as we speak. No-one has been evacuated from the station at all."
- Hundreds of yards of new paving laid as repair work to Putney Bridge pushes on
- Prolific thief jailed for breaching ASBO after dawn visit to Mitcham
- Everyone happy as Nappy Valley named the friendliest place Wandsworth
- Television calling for Battersea admin worker
- Spanish film night returns to Battersea haunt