Cleveland Police has been accused of accessing the phone records of three regional newspaper journalists.
The force allegedly used the Regulation of Investigatory Powers Act to grab the telecoms records of the Northern Echo journalists as part of a leak investigation.
The Police Federation union is understood to have made a complaint about Cleveland Police to the Independent Police Complaints Commission over the seizure of six individuals' records, including the three reporters.
In response to the allegations that his journalists' records were targeted, Northern Echo editor Peter Barron said: "These allegations are a matter of serious concern – that a police force should apparently go to these lengths to identify the source of a story which was clearly in the public interest.
"This is surely not what the legislation was intended to do and the fact that Cleveland Police will neither confirm nor deny the allegations adds to our concerns.”
According to the Northern Echo, the leak investigation related to a 2012 story revealing an internal report had uncovered "elements of institutional racism".
Cleveland Police is also alleged to have obtained the phone records of a police officer, who was suspected of being the whistleblower behind the story, the then chair of the Cleveland Police Federation Steve Matthews and a solicitor for the Federation.
Cleveland Police said in a statement: "The acquisition and disclosure of communications data is governed by the Regulation of Investigatory Powers Act 2000. Cleveland Police applies the act and relevant guidance when determining whether to make use of various RIPA authorities in support of the investigation of criminal offences. Each year the Interception of Communication Commissioners [sic] Office examine our compliance with the act.
"We are aware that an individual has provided information to the Police Federation of England and Wales, through the local Federation Chairman, regarding their opinion of how Cleveland Police applies the law and guidance relating to (RIPA). The PFEW have passed this information to the IPCC who will in due course determine their next steps."
Last year, Cleveland Police emerged as the fifth force to have used RIPA to obtain journalistic phone records to identify a source. This was after a mistaken Freedom of Information Act disclosure to Press Gazette.
The first case of a police force secretly obtaining journalistic phone records to find sources emerged in September 2014. Then, the Metropolitan Police admitted to obtaining Sun phone records to find the source of its Plebgate story.
Subsequently, Press Gazette revealed that the Kent/ Essex, Suffolk and Thames Valley forces had used RIPA in similar circumstances.
In response, Press Gazette launched the Save Our Sources campaign, which called on the Interception of Communications Commissioner's Office to require police forces to obtain judicial approval before obtaining journalistic records in this way. The law was changed in March this year as a result.
Citing the Save Our Sources petition, the Interception of Communications Commisioner's Office held an investigation into police use of RIPA to find journalistic sources at the end of last year. When published in February, it revealed that 19 forces had used RIPA in this way to obtain the records of 82 journalists over a three-year period. However, the 19 police forces have not been named by IOCCO.
Overall, there were 105 journalists at the centre of leak investigations reported to IOCCO, with 78 per cent having their own records obtained. Some 19 of the 105 were listed as working in the local/ regional press.
The draft Investigatory Powers Bill sets out in law new protections intended to stop police accessing journalists’ call records in order to identify their sources.
But there is concern from within the journalism industry that the new protections do not go far enough.
The new law will replace an interim addition to the Regulation of Investigatory Powers Act passed in March this year following Press Gazette's Save Our Sources campaign.
The draft bill states that police forces must get the approval of a “judicial commissioner” before accessing the communications data of a journalist in order to identify a source.