Cleveland Police chief Iain Spittal announced a major overhaul of the force’s Professional Standards Department, and said its replacement could be headed by a candidate from outside the police.
The review, announced with police and crime commissioner Barry Coppinger at headquarters in Middlesbrough, follows a string of scandals at the force.
Last month, the Investigatory Powers Tribunal (IPT) in London heard that the force used anti-terror legislation, the Regulation of Investigatory Powers Act (Ripa), to find out the source of damaging leaks.
The force tracked the phones of Northern Echo journalists Graeme Hetherington and Julia Breen over months in 2012 – while she was on maternity leave – as well as those of other individuals.
The force has also lost a high-profile employment tribunal, as well as facing court cases and disciplinary hearings in recent months.
Last month, James Wharton, Tory MP for Stockton South, said Cleveland Police should be disbanded and merged with neighbouring forces if it did not make improvements.
Although the IPT findings will not be released until later this month, Mr Spittal said the panel had indicated the force’s use of Ripa to find the source of leaks to the media was unlawful.
He said: “Whilst we have not received the final judgment, on behalf of the organisation, I feel it is right to apologise for the use of Ripa in 2012. As a result, before Christmas I made contact with the individuals concerned to offer personal apologies to them.”
Mr Spittal was not in charge of the force at the time of the phone tracking and said that since he joined the force in 2013 there had been no use of Ripa provisions to identify the source of leaks to the media.
The Professional Standards Department would face a “thorough review”, he said, adding: “There needs to be a fundamental change in how we deal with complaints and how we investigate wrong-doing – and now is the right time to begin the change.”
The force would also look at how other regulatory bodies operated and its new head could come from outside the police, he said.
Mr Coppinger, sitting alongside the chief constable, backed the changes but said there was no chance of the force being merged.
He said: “I was disappointed to hear, before Christmas, calls for Cleveland Police to be abolished and merged with other forces. I know that the people of Cleveland would not support this.
“Whilst I am commissioner there will be no question of this force merging with another.”