All trains from Twickenham to London Waterloo are delayed or cancelled until 12pm today, 11 June.

Railway operator South Western Railway (SWR) says "all London bound lines are disrupted" after a communication alarm was activated on a train between Wimbledon and Clapham Junction.

The scale of the disruption means a number of services have been cancelled completely while they return to their intended position in the network.

"Train services running to and from these stations are returning to normal," says SWR, estimating the disruption to be cleared by midday.

In the meantime, customers can use their tickets either on the Great Western Railway between Basingstoke and London Waterloo via Reading, or on the London Underground via "any reasonable route".

Customers are also encouraged to check their plannned route on the SWR website, available here.

While it is unclear why the train's alarm was used, SWR has a history of delays being caused by their misuse.

In 2022, the operator claimed customers incorrectly activated emergency alarms on their trains 176 times in six months, resulting in over 30 hours of delays.

Among them was a customer who used an alarm claiming they had dropped their phone out of a train window, and another who had forgotten their luggage on the platform.

Some alarms are accidentally triggered, such as on overcrowded services where passengers may be pushed against the sides of the carriage.

Alarms are intended to allow customers to alert train staff of emergencies, such as a fire or crime, with the penalty for intentionally activating an alarm incorrectly being £1,000.

Nub News will update this story as the situation develops.