The Sun today sided with the Labour Party and urged Conservative MPs to reject the Investigatory Powers Bill because it fails to protect journalists' sources.
This mirrors the position of the Labour Party and the National Union of Journalists and echoes widespread unease in the journalism industry about the proposed 'snooper's charter'.
The proposed law details widespread powers allowing the state to intercept internet and telephone communications and it has its second reading in the House of Commons today.
Concerns for journalists centre around law enforcement agencies' ability to secretly view telecoms data in order to identify journalists' sources.
Under the proposed new regime police requests to view journalists' telecoms data would need to be approved by an independent judicial commissioner. But the requests would be made in secret with no opportunity for journalists or publishers to argue the case for source protection.
The Sun said today in a leader: "Tory MPs who care about journalism — and democracy — should today reject the Investigatory Powers Bill as it stands.
"We applaud most of it. But it draws too little distinction between spooks working to prevent terrorism and ordinary cops known to abuse spying powers.
"If they could be trusted, no innocent person would need to fear their records being stored or even accessed. Yet cops have recreationally used covert anti-terror powers to expose whistleblowers who have embarrassed them.
"Reporters must be able to keep such sources secret. They are the lifeblood of journalism and thus vital for democracy. Giving police more spying powers is a dangerous folly."
The Labour Party has also said the bill needs more protections for journalists and their sources.
Shadow home secretary Andy Burnham told The Times: "We believe the bill must start with a presumption of privacy, as recommended by the intelligence and security committee, include a clearer definition of the information that can be held and set a higher threshold to justify access.
There also needs to be higher protection for journalists and their sources."
The Investigatory Powers Bill will be discussed by MPs for the first time today.
The Scottish National Party and Labour are both seeking major changes to the legislation.
The National Union of Journalists, Society of Editors and News Media Association have all voiced concerns that the bill gives insufficient safeguards to journalists and their sources.
Last year it was revealed that police forces had secretly grabbed the telecoms records of 82 journalists in order to identify their confidential sources in the previous three years.
This included the mobile phone records of three Sun journalists, and details of calls made to The Sun newsdesk. The data grab was used by the Met Police to find and sack three police officers accused of lawfully leaking information to The Sun about the Plebgate incident in which former Cabinet minister Andrew Mitchell swore at police officers outside 10 Downing Street.
After the Press Gazette Save Our Sources campaign the Government changed the law to ensure that such telecoms records requests were subject to external approval by a judge for the first time. The new legislation would replace the current arrangement.