Transport for London (TfL) today on Monday confirmed it has been dealing with what has been described as an "ongoing cyber security incident".

As an organisation responsible for most of London's transport network, this comes at the same time as major delays have been experienced at King's Cross on Monday and Tuesday.

Specific details of the cyber attack have not been revealed, although it is known that the National Crime Agency (NCA) and the National Cyber Security Centre (NCSC) have been called in to establish the damage caused by the breach.

With TfL holding customer data for millions of Londoners, some are worried that their own data could be compromised. Here's what you need to know.

TfL staff have been told they can work from home on Tuesday if that makes it easier to carry out their roles amid measures put in place in offices.

Transport for London has confirmed that it doesn't believe any customer data has been compromised.

In a statement, 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, 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."