There is the threat of disruption to rush hour bus services on London’s biggest operator after Go-Ahead was hit by a “cyber security incident”.

It is understood that bus and driver rosters were among areas targeted by the apparent hackers on Monday.

Any delays to services would be posted on the relevant Twitter account, a spokesman confirmed to Sky News.

Go-Ahead, which is also a major in Brighton and Newcastle, said the incident was ongoing.

Its statement said: “Go-Ahead announces that it is currently managing a cyber security incident after detecting unauthorised activity on its network on Monday 5 September 2022.

“Upon becoming aware of the incident, Go-Ahead immediately engaged external forensic specialists and has taken precautionary measures with its IT infrastructure whilst it continues to investigate the nature and extent of the incident and implement its incident response plans.

“Go-Ahead will continue to assess the potential impact of the incident but confirms that there is no impact on UK or International rail services which are operating normally.

“As a precaution, Go-Ahead has notified relevant regulators, including the Information Commissioner’s Office in the UK.”

Go-Ahead London is the capital’s biggest bus operator, operating over 2,400 buses.