In the first exercise of its kind in the UK, the government will simulate a "total collapse" of the national phone network next week, as part of the National Strategy for Cyber Security launched by Gordon Brown in June.

The move was announced at the House of Lords EU Sub-Committee on Home Affairs yesterday.

The exercise will take place on 11 and 12 November and be codenamed White Noise. It will be designed to simulate a complete shutdown of the public switched telephone network (PSTN).

White Noise will involve hundreds of government and industry players but will not have any impact on those not involved in the exercise.

The government’s response will be monitored by officials in a co-ordinated way and the results will be relayed to Parliament and the public.

Speaking at the House of Lords EU Sub-Committee on Home Affairs, Geoff Smith, head of communications security in the Department for Business, said: “[White Noise will teach us] whether we can respond [to a crisis like this] in real time.”

He added: “Without a functioning communications system we would be reduced to carrier pigeons and semaphore.”

This exercise follows a number of concerns raised by the Lords committee about the adequacy of protection and responsiveness of infrastructure regarding cyber-attacks.

Smith said: "Analysis of the response to White Noise will add momentum to efforts across government to strengthen the UK's communications infrastructure. "

The national strategy for cyber security is part of the wider national security system and aims to increase protection against cyber crime in the digital age and build on themes introduced by the Digital Britain report.