A "very sophisticated" cyber attack which put thousands of customer details at risk has delayed the rollout of contactless payment to eight trains stations near Watford.

Rail passengers had been set to use their bank card or smartphone to pay for train travel at Watford North, Garston, Bricket Wood, How Wood, Park Street, St Albans Abbey, Kings Langley, and Apsley from Sunday, September 22.

But now London Northwestern Railway, which runs the stations, has confirmed it has been postponed after a cyber security incident left Transport for London unable to “deliver the necessary system changes”.

Contactless payment had been set to be introduced on September 22.Contactless payment had been set to be introduced on September 22. (Image: TfL)TfL has admitted that thousands of customers’ details, including home addresses and bank details, are thought to have been accessed in the attack which was first identified on Sunday, September 1.

The attack is described as "very sophisticated and direct" by chief technology officer Shashi Verma, who told the Evening Standard it was not clear how long it will take the transport authority to fully recover.

A 17-year-old boy was arrested in Walsall on Thursday, September 5, on suspicion of Computer Misuse Act offences in connection with the attack and was later bailed after questioning, the National Crime Agency has said. 

The new date for the pay-as-you-go launch has yet to be confirmed, although LNR said it is working with TfL to reschedule the launch.