Millions of students due to sit exams this week were disrupted as a cyberattack brought down the University of London Computer Centre’s (ULCC) IT systems for more than four hours on Thursday morning.

Admins at the university were alerted to the problem as pupils took to social media to complain about the outage, which brought down a number of virtual learning tools from 150 schools around the country.

Among the groups affected were the industry body Universities UK, IT services provider Jisc and universities in Manchester, Warwick and London.

Caught up in the attack was Moodle, a virtual learning environment used by millions of students in universities across the country, which faced a complete shutdown from 7.30 until just before noon.

A statement released by ULCC at midday on Thursday read: "All our services are now up and running again! The networking issue was caused by a cyber attack.

"We have taken action to block the source. An incident report will be produced and shared in due course."

Though the university declined to specify what the nature of the attack was, it is rumoured that it was some sort of denial-of-service attack, in which large volumes of traffic clog up a service, leading to slowdown and crashes.

ULCC could not be reached for further comment at this time.