Sir John Hermon was chief constable in the 1980s
The former chief constable of the RUC Sir John Hermon has died.
Sir John, known as Jack, was chief constable between 1980 and 1989. He first joined the force in 1951.
His wife, Lady Sylvia Hermon, is now the Ulster Unionist Party's only MP. She has held the North Down seat since 2001.
Sir John had Alzheimer's disease for several years. He died in a nursing home in Bangor, County Down, on Thursday evening.
"It is with enormous sadness that the family of Sir Jack Hermon announce his death, after a long and valiant struggle against the ravages of Alzheimer's," a family statement read.
"He passed away very peacefully at teatime yesterday in a nursing home in Bangor.
"Members of his immediate family, including his wife, Sylvia, had been with him throughout the day."
His period as chief constable was one of the most turbulent periods of the Troubles, including the 1981 republican hunger strikes and probes into the controversial so-called shoot-to-kill allegations made against the RUC.
Sir John was also chief constable when the RUC suffered its biggest single loss of the troubles, when nine officers were murdered in an IRA mortar attack on Newry police station in 1985.
He remained a target for republicans long after leaving office - last year he had to be moved from another nursing home because of a threat.
Former RUC assistant chief constable Alan McQuillan said Sir John was "a huge figure in the history of the RUC".
"Sir Jack was a very energetic and dynamic leader, but when you got to know him you saw he was driven by a total passion for impartial policing, for protecting the community and an immense pride in the men and women who served in the RUC," he said.
The Police Service of Northern Ireland chief constable Sir Hugh Orde spoke to Lady Hermon last night to express his sympathy and pass on his condolences to the family.
Secretary of State Shaun Woodward said Sir John had earned "deep and lasting respect".
"He was undoubtedly a strongly committed and dedicated police officer, leading the RUC through some of the most demanding, difficult and dangerous years," Mr Woodward said.
DUP leader Peter Robinson said: "Jack Hermon was the chief constable of the RUC at a very difficult time in Northern Ireland's history.
"As the leading police officer in Northern Ireland during this period he was to the fore of the battle against terrorism and he played a leading role in stamping it out."
'Courage and determination'
Ulster Unionist leader Sir Reg Empey said he was deeply saddened by Sir John's death.
"I know Sir Jack will be sadly missed by Sylvia and his family to whom we extend our deepest sympathy for their loss," he said.
Alliance party leader David Ford said Sir John led the RUC with "courage and determination".
"He set an example which should inspire members of the PSNI in these different times," he said.
Former SDLP deputy leader Seamus Mallon said Sir John had all the qualities of a good police officer, but these had not been allowed to operate in the running of an impartial force.
He said Sir John was "caught in the trap" of the police being the "protectors of the state and the constitutional position, rather than the enforcers of law and protectors of the individual".
Sinn Féin's Martin McGuinness said he extended his sympathy and condolences to the Hermon family.
"Jack Hermon was the chief constable of the RUC during a particularly intense period of the conflict. Today we are still grappling with the legacy of that. However, this is not the day to dwell on that," he said.