David Carroll played a leading role in a city-based agency operation specialising in computer hacking and telephone tapping.
Active Investigation Services made its money from broken marriages, family disputes, and even industrial espionage.
London’s Southwark Crown Court heard that behind its veneer of respectability lay a “backbone of dishonesty” and its lucrative “Hackers Are Us” sideline.
Its well-heeled customers included banking heir Matthew Mellon, the agency’s job being to discover his estranged wife’s financial secrets.
Clients could choose from a shopping list of confidential information.
Phone tapping cost £3,000 (€4,000), itemised line billing was priced at £750 (€1,000) a month, while personal banking information could be bought for £2,000 (€2,600) and confidential medical records for £500 (€670).
Hacking into a computer, using viruses made to order by a US expert, was available for £5,000 (€6,700). The company even stooped to illegally using disabled car parking badges during operations.
Carroll, 60, from Highgate, north London, was convicted earlier last year of six conspiracy counts.
They alleged that between September 2003 and September the next year he hacked into computers and tapped telephones
Passing sentence, Judge Paul Dodgson told him “he was quite convinced from the evidence” Carroll had been the “right-hand man” of agency chief Jeremy Young, 40, a former Met officer, who was jailed last year for 27 months.
Dismissing a probation officer’s non-custodial recommendation as “ridiculous”, the judge added that prison was inevitable for such serious offences, despite the suffering this would cause to the defendant’s elderly mother and young step-son.
Miranda Moore, QC, prosecuting, said Young first came to the attention of the authorities after colleagues discovered him at the agency’s helm while taking long-term sick leave for depression.
Complaints of phone intercepts began flooding into BT at about the same time.
Engineers later found that hundreds of made-to-order tapping kits had been installed across the country by a former telephone engineer on the agency’s payroll.
The court heard that Carroll’s tenure at the agency saw him involved in efforts to spy on a waste management company’s critics, tap the phones of a client’s wife suspected of having an affair and target Ms Mellon.