Transport for London (TfL) has revealed it is dealing with an “ongoing cyber security incident”.

The organisation, which is responsible for most of London’s transport network, has not shared specific details of the incident but it confirmed there is currently no evidence customer data has been compromised.

Shashi Verma, TfL’s chief technology officer, said: “We have introduced a number of measures to our internal systems to deal with an ongoing cyber security incident.

“The security of our systems and customer data is very important to us and we will continue to assess the situation throughout and after the incident.

“Although we’ll need to complete our full assessment, at present, there is currently no evidence that any customer data has been compromised. There is currently no impact on TfL services and we are working closely with the National Crime Agency (NCA) and the National Cyber Security Centre (NCSC) to respond to the incident.”

A spokesperson for the NCA said: “We are aware of a cyber security incident involving Transport for London (TfL), and are working closely with the National Cyber Security Centre, and with TFL itself, to respond to it.

“The investigation is ongoing, and we are unable to comment further.”

A spokesperson for the NCSC confirmed it was working with TfL and law enforcement partners “to fully understand the impact of an incident”.