Contingency plans made by the Government to deal with disasters such as a plane crash are being largely declassified as part of a change to Government Security Regulations. The plans, previously officially graded as confidential, are to be unrestricted except for 'matters where the disclosure of the content of such plans would prejudice their effective implementation'. Government security officer John Ng Sheung-lok said the changes were part of a move to have fewer secret files but ensure that those which remained secret would be properly handled. 'If there are too many secret files, vigilance will be automatically lower,' he said. The Government has about 12 contingency plans. Four - dealing with internal security, terrorism, mass escapes from Vietnamese detention centres and safety during visits by nuclear-powered warships - will remain classified in entirety. Those now largely declassified include those for an aircraft crash, accidents at installations on Tsing Yi Island, a mass influx of illegal immigrants and a wide range of natural disasters. The sections that will remain classified will include key telephone numbers. Mr Ng said that general principles, the responsibility of individual departments and overall approaches would no longer be classified. The first cracks in the policy of keeping the plans secret appeared a few years ago when plans for dealing with a nuclear incident at the Daya Bay nuclear power station were published. The new regulations state, for the first time: 'The fact that a document or information may cause embarrassment or expose a department to criticism is not, in itself, valid grounds for applying a security classification.' But Mr Ng conceded that in some cases, classified files might contain little more than selected press cuttings. But he said the assembled cuttings could constitute 'intelligence'. The new regulations, issued at the end of last year and obtained under the Code on Access to Information, show the Personal Data (Privacy) Ordinance means a large amount of low-level personal information must now be restricted. 'In the past we found some people were handling personal data rather loosely,' Mr Ng said. Political scientist Professor Joseph Cheng Yu-shek of City University said there were 'obviously too many classified files'. He doubted whether many files in the lower classifications needed to be classified at all.