Fears are mounting that a sophisticated virus known as Stuxnet, which played havoc with the Iranian nuclear weapons programme, could now pose a threat to other real world targets.

Cyber security experts are concerned that the virus code has been traded with terrorists, who have the capability to deploy the virus against civilian targets such as power stations, hospitals and even traffic lights.

Sky News quote an unnamed IT security source who said: "We have hard evidence that the virus is in the hands of bad guys – we can't say any more than that but these people are highly motivated and highly skilled with a lot of money behind them.”

Industry experts point out however that sensitive infrastructure can be easily protected, just disconnect it from the web.

UK politicians are taking the threat of cyber terrorism increasingly seriously however, regarding it as a “tier 1” threat to national security.