Thalha Jubair (now 20) and Owen Flowers (now 18) face sentencing after prosecutors describe an “extremely serious” cyberattack on Transport for London (TfL) carried out between 31 August and 3 September 2024. The two were linked to the hacking group Scattered Spider and were accused of gaining access to TfL’s online network after tricking a helpdesk password reset and then using TfL systems to deepen the intrusion. Court heard they obtained the highest level of access and that TfL feared the attackers could place ransomware across systems or otherwise lock or destroy the central TfL infrastructure.

Prosecutors said the potential consequences could have been catastrophic, including large-scale disruption to transport services and wider impacts on essential services. A victim statement read to the court said the disruption could have affected education, healthcare and other areas relying on transport, with significant economic harm. The accounts also state TfL responded by “pulling the plug” on parts of its system, requiring all of its more than 27,000 employees to reset passwords.

Both defendants admitted conspiracy to commit unauthorised acts involving computers causing or creating risk of serious damage. Flowers additionally admitted counts involving conspiracy to impair healthcare systems. They are scheduled to be sentenced on Thursday.