An Investigatory Powers Tribunal (IPT) concluded Police Scotland’s actions were contrary to the Human Rights Act of 1998.
Two former police officers and their wives, together with two serving policemen, took the action to “complain of the collateral interference with their privacy”.
It comes after Sir Stanley Burton, the Interception of Communications Commissioner, ruled in November 2015 that Police Scotland contravened the acquisition and disclosure of communications data code of practice on five occasions.
The Interception of Communications Commissioner’s Office (IOCCO) conducted a review after fears were raised officers had been ‘’illegally spying on journalists’’, in incidents linked to the investigation into the murder of prostitute Emma Caldwell in 2005.
Gerard Gallacher, a former police officer who carried out an 18-month journalistic investigation into the case, is to be paid £10,000 after telling the tribunal he had suffered an “invasion of privacy, familial strife, personal stress and strain and loss of long-standing friendships” as a result of Police Scotland’s actions.
The IPT ruled the interference with his rights to freedom of expression were “serious in respect of the obtaining of more than 32 days of communications data”.
Of the six complainants, only Mr Gallacher and his wife had been seeking compensation.
The tribunal also ordered that an inquiry into the breach of guidelines be conducted by a senior officer “from another police force without any previous relevant connection with Police Scotland”.
At the end of July, Phil Gormley, the Chief Constable of Police Scotland, asked Mike Barton, Chief Constable of Durham Constabulary, to head an independent investigation into the issue.
Detective Inspector David Moran, one of the complainants in the case, welcomed “the judgment of the IPT in connection with their examination of Police Scotland’s unlawful actions in trying to ascertain the sources of a journalist” after a newspaper published an article which was critical of the Emma Caldwell murder investigation.
Police Scotland Deputy Chief Constable Iain Livingstone said the force would “consider and act” on the findings of the IPT.