The Police Ombudsman has concluded that a police officer's decision to fire a warning shot when a group of youths stepped onto a road and forced a police car to stop near west Belfast in July 2006, was "unnecessary and unjustified."

The unmarked police car was travelling along the Old Golf Course Road at around 2am on 22 July 2006 when the youths stepped out in front of it.

The three officers travelling in the car later told Police Ombudsman investigators that they believed the youths had not recognised the car as a police patrol and had been attempting to rob them or hijack the vehicle.

As the police car drew to a standstill, the officer travelling in the front passenger seat opened his door in order to challenge the youths. He said that as he did so a hooded male, who had moved quickly to the passenger door, produced a handgun from his jacket.

The officer then closed the car door, drew his personal protection weapon and fired what he described as a single "aimed warning shot" through the windscreen.

The youths fled from the scene and the driver continued for a further 200 metres along the road before stopping to check for injuries.

In line with standard procedure, the PSNI referred the firearms discharge to the Police Ombudsman for independent investigation.

The police car, incident scene and firearm were all forensically examined, and statements were obtained from the officers involved. Checks were also made for any CCTV footage or civilian witnesses, but there was no housing in the immediate area, nor any nearby CCTV cameras.

The three officers who had been travelling in the police car provided similar accounts of the incident, but only the officer who discharged the shot said he had seen the youth beside his door drawing a handgun.

He told investigators that he had made a "split second" decision to shoot in response to what he considered to be "a very real threat." He said that by aiming the shot he had minimised the potential for injury or death and considered his actions to have been proportionate to the situation.

A forensic examination of the police vehicle provided evidence which corroborated the officer's account of his position when he discharged the shot. A bullet fragment was also recovered from the vehicle's dashboard.

Further enquiries established that the officer had failed to maintain an appropriate level of training in the use of his personal protection weapon. He had not attended refresher training in the use and handling of his PPW for two years, whereas PSNI policies requires such training at six-monthly intervals. He claimed there was a lack of clarity as to who should make arrangements for such training.

Having reviewed the case, the Police Ombudsman, Mr Al Hutchinson, said: "Warning shots should only be used in the most exceptional circumstances when failure to do so would result in the loss of life or serious injury, and only in full consideration of public safety.

"As far as possible, officers should also adopt a graduated and flexible approach, applying non-violent methods before resorting to the use of force."

In this incident, he said that the risks associated with the officer's actions were demonstrated by the fact that a bullet fragment had been recovered from the car's dashboard.

"Although the officer was adamant that he believed both his own life and those of his colleagues were in danger, and that he had no option but to discharge his firearm, the discharge of the firearm was not absolutely necessary in the circumstances, and actually endangered himself, his colleagues and members of the public," said Mr Hutchinson.

The officer has since been disciplined in respect of his actions, and the PSNI has also acted on a recommendation from the Police Ombudsman by reminding officers that it is their personal obligation to ensure they are fully trained and qualified in use of their firearms.