PRESS ASSOCIATION -- The Metropolitan Police are seeking an order under the Official Secrets Act to force The Guardian to disclose the confidential sources of its reports on the News of the World phone hacking scandal, the paper said.
Editor Alan Rusbridger strongly condemned the move as "vindictive and disproportionate", and said the paper would resist it "to the utmost".
Among the information the police are said to be seeking is the source of The Guardian's report disclosing the mobile phone of murdered teenager Milly Dowler had been hacked which prompted a massive public outcry.
"It seems to me an extraordinarily heavy-handed use of the Official Secrets Act which is basically about espionage and international relations and things like that to defeat the privilege journalists have to protect their sources," Mr Rusbridger told BBC Radio 4's PM programme.
"What they are trying to do is to find out the source of the embarrassment of the articles - and no doubt The Guardian's coverage was embarrassing to the police. It looks vindictive and it looks ill-judged and disproportionate."
The paper said the police intended to go before a judge at the Old Bailey on September 23 to apply for an order under the Official Secrets Act 1989 requiring it to hand over documents relating to the source of information for a number of articles.
Scotland Yard confirmed it had applied for a production order against The Guardian and one of its reporters "in order to seek evidence of offences connected to potential breaches relating to Misconduct in Public Office and the Official Secrets Act".
"The application is about the MPS seeking to identify evidence of potential offences resulting from unauthorised leaking of information," it said in a statement.
"Operation Weeting is one of the MPS's most high profile and sensitive investigations so of course we should take concerns of leaks seriously to ensure that public interest is protected by ensuring there is no further potential compromise. The production order is sought in that context.
"The MPS can't respond to the significant public and political concern regarding leaks from the police to any part of the media if we aren't more robust in our investigations and make all attempts to obtain best evidence of the leaks."