When the Operation Barbatus team began investigating illegal phone taps they had no idea they would uncover a criminal web involving several fellow police officers.

Following a tip-off from British Telecom, they linked the taps to a private detective agency in London and put it under surveillance.

It was then that Det Insp Kevin Hyland and his team made the alarming discovery that the agency was being run by a Metropolitan Police constable.

Jeremy Young, now 40, was supposed to be on sick leave, but there he was running a lucrative sideline - Active Investigation Services (AIS).

Alongside him, the Barbatus team also found a former Met Pc - Scott Gelsthorpe, now 32.

The full extent of the corruption emerged after the offices of AIS were raided and their 60 or so computers analysed.

It was then clear that Det Sgt John Matthews, of Staffordshire Police, and two former detectives from the same force, Gary Flanagan and Anthony Wood, were also involved in crooked private eye work.

All insisted in mitigation that they were or had been hard-working officers with long periods of unblemished service to their names.

Det Insp Hyland said: “It’s very upsetting. The vast majority of serving police officers are honest and hardworking, but the very small number that aren’t reflect badly on the police service as a whole.

“Then there’s the fact that this case involved private investigators in London, Hereford and Staffordshire and had police connections in all those areas.

“It is quite alarming because it’s a national network they’ve set up.”

Operation Barbatus lasted three years and involved eight police forces, plus the FBI and police in the Republic of Ireland, where AIS was looking to expand its operation.

Det Insp Hyland’s team went to great lengths to gain convictions, gathering one million e-mails from AIS’s computers.

A staggering 250,000 of those were analyzed in detail by one officer working 13-hour days - he eventually spent four weeks in the witness box.

Double life

Young and Gelsthorpe claimed on their website to be ex-Scotland Yard detectives when, in fact, they had been uniformed officers and had no specialist detective training.

They met when they were both working at Stoke Newington police station in Hackney, east London.

Young had joined the Met in 1987, while Gelsthorpe had joined in 1991.

Ex-police private eyes jailed

Gelsthorpe left the police in 1996, but Young carried on a double life from the time of AIS’s creation in 1999.

“It was about that time that Jeremy Young started a pattern of going sick from the Met. Stress, anxiety, sometimes back pain. He would come back for a while and then go off sick again,” Det Insp Hyland said.

“In total, we worked out he had taken 1,640 sick days in five years.”

Young denied running AIS right up until the day of his trial when he changed his plea.

In mitigation, his barrister, Alun Jones QC, insisted he had been “a valued member of the Metropolitan Police force” until an accident in 1996 which left him with depression.

Two of Young’s former colleagues told the trial he had once been a “proactive” and “keen” officer who was a “very good thief-taker”, but whose character had changed utterly.

Abandoned vehicles

The activities going on in Staffordshire were also discovered indirectly from information on AIS’s computers.

Police found that Matthews was abusing his position as supervisor of the call-handling centre and member of the steering committee which managed use of the police national computer (PNC).

Matthews had joined the police in 1975 and his counsel Brian Dean said he had an otherwise “impeccable” record, even being commended for tackling “a deranged man with a knife”.

Yet he used his job to hide his illegal activities.

He was supposed to oversee legitimate checks on the ownership of abandoned vehicles, but on 128 occasions when he was checking the PNC, he was also on the phone to a private detective agency called Brian Harrison Investigations (BHI) in Stoke-on-Trent.

On 87 occasions, Matthews was checking vehicles for BHI, but on inspection, police saw they included Bentleys, Mercedes and even a car with British Services plates - not abandoned wrecks.

The rest of the checks - 41 in all - were on individual people.

All of this information was going to Wood and Flanagan who ran BHI.

Commendations

Wood had served in the police for more than 30 years from 1961 to 1993, and was a former colleague and close friend of Matthews.

He too had been commended several times, once for his involvement in the Carl Bridgewater appeal which saw two men cleared after wrongly serving 18 years for murder.

According to his counsel Ian Bridge, “he has an absolutely first class record of contribution to society in general”, yet he too broke the law.

Prosecutor Miranda Moore QC told Southwark Crown Court that as serving and former police officers all three “could be under no illusion” as to the seriousness of their actions.

But Mr Bridge said his client had joined the police force before data protection was taken seriously.

He played down the severity of the crime saying: “There are no victims who reported a crime. No harm was done to any individual.”

But Det Insp Hyland was clear: “The public expect to have faith in the police and expect the police to respect the information they hold, so to sell it or pass it on without a lawful reason is totally unacceptable.”

Matthews, Wood and Flanagan and were convicted of misconduct in a public office and received 14, 10 and three month sentences respectively.