Nuala O’Loan, the Police Ombudsman said the officer was right to open fire, however, she criticised aspects of the operation and questioned the reasoning behind the apparent deletion of vital records in the aftermath of the incident.

The 21-year-old Neil McConville was shot three times as he tried to evade police in a car near Lisburn in April 2003.

Mrs O'Loan said the officer feared for his colleague’s life, who had been knocked to the ground in front of the car.

Another man in the car was shot and injured in the incident at Ballinderry Upper.

He was later jailed for four years for possession of a sawn-off shotgun found in the vehicle.

But the ombudsman expressed ‘grave concerns’ that some intelligence information about the police operation had been deleted from a computer during her investigation.

She said she found it hard to believe evidence was deleted accidentally after her office had requested the information.

Mrs O’Loan criticised the police operation on the night and suggested to the Chief Constable the two officers in question should be removed to less critical duties.

She also criticised a number of senior officers who refused to co-operate with her inquiries and then retired while possible misconduct issues were being considered.

The police officer who fired the fatal shots said his firearm was accidentally switched to automatic instead of single fire, and when he intended to fire one shot he actually fired three.

The police said they had worked hard in recent years to ensure that all officers were aware of their duties and responsibilities to co-operate with police ombudsman investigations.

In a response to the report, the PSNI said: "The police service regrets the death of Neil McConville as we would the death of any citizen who loses their life in the course of a police operation.

"We note the contents of the report and its finding that the officer who fired the fatal shots was justified in using his firearm to protect the life of a colleague.”

MLA John O'Dowd expressed concern at the number of PSNI officers recommended for disciplinary hearings that retired following the incident and the impact that this has had on the Police Ombudsman's investigation.

He said: “It is essential that we have proper openness and full accountability.

"It is a huge cause for concern that all of the officers who were recommended for disciplinary hearings have retired,” he said.

“This has meant this investigation by the Ombudsman has not been able to look at all of the relevant facts or interview all of the relevant personnel.

“This will only undermine public confidence in the PSNI and their commitment to openness and accountability,” he said.

"I know that the family are disappointed that this has not been properly investigated, the police cannot kill people on our streets and think they will not be made accountable for such actions,” he said.