THEY say there are certain events in our lives which, when they happen unexpectedly and tragically, always imprint indelibly in our minds what we were doing at the time we heard of them. Where were you when President Kennedy was assassinated, or when Princess Diana was killed?

There's another for the officers and staff of Hertfordshire Constabulary. On Thursday, April 14, 1988, I happened to be driving from the police headquarters of another force, Essex, an otherwise unmemorable event. But I remember it exactly because it was then the news broke over the car radio that PC Frank Mason had been murdered.

He had been walking his dog when he came upon an armed robbery in progress at Barclays Bank, Bank Court, Hemel Hempstead.

A man was brandishing a handgun at a security guard. Frank would have seen this perfectly well and yet, off duty, he tackled the gunman. He was fatally shot in the back by another man, the gunman's accomplice.

Forever after, throughout my police career, I never lost sight of the situation, still prevailing today, that when senior officers, as I was, are dispatched to attend "management courses", it's up to the front line, street coppers, in this case one not even on duty, who are actually facing the crime the streets.

Frank Mason was 27 years old, with four years in "the job". A few years before, at Hemel Hempstead, I met the young probationer constable. A smile and a "morning guv" was all I knew of him.

He was married, no children. Before he joined the force he had been a young reporter with the Watford Evening Echo. A former colleague described him as "one of the most honest men I have known. What he did doesn't surprise me, it was the sort of thing he would have done without thinking."

Three men were responsible for this crime. They, with others, had come to the notice of officers of the Regional Crime Squad. They were Charles McGhee, 30, Perry Wharrie, 28, and James Hurley, 26. The information was that Charles McGhee "was doing armed robberies and had the use of firearms". A fourth man, Robert McFarland, 32, was also named as one of the team, but he would not take part directly in the tragic events at Hemel Hempstead.

The men had premises in Luton, and RCS officers took up observations over two phases intelligence gathering, and mobile surveillance. The alternative to this strategy was to arrest them, but without direct evidence they would simply have been released. Even so, careful consideration was given to charges of conspiracy, and the Crown Prosecution Service was consulted.

Again, there was insufficient evidence, only "information", which on its own cannot provide proof of criminal activity or even intent.

So, to get the evidence they needed, the police would have to employ the tried and trusted way: observations and patience.

These were the tactics of the "Regional", who were equipped with electronic and other surveillance equipment, as well as cars and, of course, their expertise as detectives. As one who served on the Regional for eight years in two different police forces, I can vouch for their tactics. This is what they are for; they target suspects and operate where other methods cannot succeed.

The gang had use of three vehicles, at least two of which were stolen. The police watched and waited. They waited ages, as they do. It's the only way.

Finally, McGhee, Wharrie and Hurley (a getaway driver) left Luton in a convoy of two vehicles and headed south down the old A6.

They passed through Harpenden, at no time in actual sight of following police, but being tracked by a special electronic device attached to one of the criminals' cars. Fine so far, except the speed they travelled made it impossible to maintain close contact. Without direct sight of their targets, the following police could not possibly keep up. Instead, they could only plot the route, thanks to the tracker device, and follow.

The gang drove to Hemel Hempstead. It seems they were intent on attacking a security van, one of several which would call at the banks at the appropriately named Bank Court. When they arrived, one was already there, and such was the timing it could not possibly have been the one they intended. But it was there, and so were they. James Hurley, the getaway driver, remained in one of the cars while McGhee and Wharrie, both armed, went off to rob.

Frank Mason, approaching from nearby Waterhouse Street, would have seen the security van and a man holding a gun. He had no knowledge of the robber's identity, nor that he and others were targets of the Regional Crime Squad. Without hesitation he tackled the man with the gun. As Mr Michael Kalisher QC told the jury at Southwark Crown Court: "He saw the robbery taking place and with considerable courage, because he must have seen they were armed, decided to tackle the parties." Calmly stated, and understated. "Frank had bottle" would have sufficed.

PC Mason was shot in the back at close range with a Colt revolver. The robbers escaped with £15,480 in cash and cheques worth £86,000. Mansell Davies, a school caretaker, gave chase in his car, itself an act of bravery. But McGhee and Wharrie made their escape, hi-jacking another getaway vehicle.

Sara Jones, a nurse, rushed to Frank Mason's side where he lay dying on the pavement. She covered him with her coat and applied cardiac massage, and a passer-by gave mouth-to-mouth.

Sara said: "He had lost blood from a wound in his back. He was semi-conscious, slipping away, I could tell." Someone brought a first aid box from one of the banks. An ambulance came and took Frank to West Herts Hospital where he died. Floral tributes appeared outside the bank. And the Regional went hunting for the killers.

They staked out a shop in Luton, known to be used by the gang. Two hours later Robert McFarland, one of the gang, appeared and went inside. He was carrying a holdall. He emerged with James Hurley, the getaway driver, carrying dustbin liners and both went to a lock-up garage where they were arrested.

Inside the garage the police found guns, including a sub-machine gun, and ammunition.

Soon afterwards a taxi arrived at another address and when McGhee and Wharrie emerged they too were arrested. Most of the stolen money and cheques was recovered in the men's possession.

McGhee, Wharrie and Hurley were charged with murder, robbery and possession of firearms.

McFarland was charged with conspiring to rob and assisting the gang after they had committed an arrestable offence. Their arrests had been swift after the crime, but what are we to make of comments in the national press about "the police allowed the gang to slip from their grasp", and "were a mile away when PC Mason was shot?" And, for that matter, why didn't they arrest the men before the crime occurred?

It is easy to be wise in hindsight, moreso when it comes to dealing with criminals. In a criminal justice system that demands firm proof before conviction, there is no point in arresting suspects without firm evidence, especially, as the law provides, they "do not have to say anything". The Crown Prosecution Service had found insufficient evidence to charge conspiracy. And when the robbers went mobile on the day of the crime it was physically impossible to maintain contact except, perhaps, if the pursuing police drove recklessly, as the robbers would have done, risking the lives of the citizens of Harpenden.

As for the tracking device attached to the robbers' vehicle, such electronic gadgetry was once kept secret by police officers, but in this case it was mentioned openly in court and in the national press, and today you can see them using them on television. It provides an excellent means of maintaining contact with criminals in extreme cases as this surely was although one wonders how the police stand now when using such equipment in today's climate of human rights.

Criminals' rights, more like: does anyone imagine they fix them to the cars of law-abiding citizens?

McGhee and Wharrie were convicted of murder. It was never firmly established which of them PC Mason tackled, and who shot the officer. But it seems likely that McGhee pulled the trigger. The court was told that "Charlie McGhee was a pathological hater of police". Both he and Wharrie were sentence to life imprisonment, in McGhee's case with a recommendation he serve a minimum of 18 years. In fact, he died in prison. Hurley was convicted of robbery and firearms offences and sentenced to ten years. McFarland got three years for conspiracy.

Frank Mason was awarded the Queens Gallantry Medal for his bravery, and a memorial to him now stands in Bank Court, Hemel Hempstead. It was placed there through the Police Memorial Trust, whose chairman at the time, film director Michael Winner, said: "The police get a great deal of criticism. But when they do deeds of great bravery the very least the public can do is to say thank you'." Another understatement, if ever there was.

March 3, 2003 17:00