Nick Clegg, who said secrecy would only be legitimate in the eyes of the public if there was proper accountability. Photograph: John Minchillo/AP  Nick Clegg has welcomed "a totally legitimate debate" concerning powerful technologies deployed by the security services, but said some of the technical detail published by the Guardian from Edward Snowden would be of use to technicians among terrorists.  The deputy prime minister also called for a debate about the accountability of the security services, and admitted that the regulations covering their activities were designed for a different age.  His remarks suggest he may be willing to reopen the debate about the communications bill that he vetoed earlier this year as disproportionate.  Speaking in the wake of criticism of the Guardian by the security services, Clegg, speaking on Thursday on LBC's Call Clegg programme, said: "I certainly agree that if what you end up doing is publishing very technical information that most Guardian readers, and most of us frankly, would not understand and the only people who would understand are the technicians amongst the terrorists, then what is the public interest in that?"  On Wednesday Downing Street offered strong support to Andrew Parker, the MI5 director general, who had described leaks as a "gift" to potential terrorists, although he did not mention Snowden by name.  Alan Rusbridger, the Guardian's editor-in-chief, defended the paper's reporting on Wednesday, saying the NSA files had exposed formidable technologies that went beyond anything imagined by George Orwell. Rusbridger said: "They [the authorities] have information they couldn't dream of harvesting 10 years ago and they will always want more. There has to be a balance."  Rusbridger also said there was a contrast between the hostile official British reaction to the disclosures and the response in the United States, where Barack Obama has called for a debate on the extent of state surveillance.  On LBC Clegg said: "There is a totally legitimate debate to be had, and in my experience from speaking to people in the security services they recognise this, about the use of these incredibly powerful technologies.  "We have legislation – regulations – that were designed for an age that is quite different now. Both terrorist states and security services conduct this battle online in a way that was quite unimaginable just a few years ago. What that means for privacy and proportionality is a totally legitimate area for debate. How you hold the secret parts of any state to account is an incredibly important tissue."  He said: "We have to defend the principle of secrecy but you can only really make secrecy legitimate in the eyes of the public if there is a proper form of accountability."  He said the system of accountability had been improved under the coalition. But he then added: "I saw a previous head of MI5 say recently just to expect the public to accept some slightly opaque arrangement at Westminster is the way to hold everyone to account in which the public do not have much of an insight. I think it is right to ask whether there is anything more we can do to make sure the public feel accountability is working in this area properly."  Asked if the Guardian had gone too far in the level of detail it published, he replied: "I have got no doubt that some parts of what was published, which will have passed most readers of the Guardian completely by because they were very technical … were of immense interest to those who wish us harm."  Asked if the Guardian had been wrong, he said: "There is a totally legitimate debate about the power of these technologies, about how you get the balance right, how you do make sure these technologies are used in an accountable and proportionate way, but I don't think just giving technical secrets to those who wish to do us harm serves any purpose."
Deputy PM says regulations were drawn up in different age, but claims some Edward Snowden leaks could be of use to terrorists