A failed three-year police investigation of a filesharing website, run in cooperation with the music industry, cost taxpayers at least £29,000, and probably much more.

Figures released by Cleveland Police detail some costs of Operation Ark Royal, a raid on invitation-only BitTorrent site OiNK.cd.

The probe was launched with a high-profile dawn raid in 2007 and ended this January with the failed prosecution of Alan Ellis, the Middlesbrough man who ran OiNK.cd, on charges of conspiracy to defraud. He was acquitted by a Middlesbrough jury, to the anger of the BPI and IFPI.

Immediately following the trial, The Register wrote to Cleveland Police under the Freedom of Information Act for details of the costs of the controversial operation. Following delays the request was twice refused, with an official writing: "It is my belief that disclosure could undermine any ongoing and future investigations and cause potential damage to the criminal justice process."

The data was eventally released this month after intervention by the Information Commissioner's Office. It reveals:

More than £7,800 spent on police overtime

More than £15,200 on forensics

More than £4,300 on travel and subsistence for investigators

Cleveland Police point out that the investigation did not only cover Mr Ellis, but also four uploaders to the site who pleaded guilty to lesser charges last year. The case against a fifth was dropped following Ellis' acquittal.

However, the force admits the true total cost is likely to be significantly greater than disclosed because it did not keep records of normal hours spent on the case, or the involvement of other forces.

When it was launched, with TV cameras invited to record Ellis being led from his home in handcuffs, Operation Ark Royal was trumpeted by Cleveland Police as the result of "working closely with the music industry... the first such international operation in the country". It was viewed as a coup for the music industry, as the first time British criminal law had been used to attack a BitTorrent site.

Ellis' barrister Alex Stein suggested at his trial that authorities had been hoodwinked into action. "All of us here are being manipulated to some sort of marketing strategy by the IFPI. If anybody's acting dishonestly it's them," he told the court.

The failure of Operation Ark Royal to secure a conviction against its main target may mean police are less inclined to get involved in future online copyright issues. But to the record industry's consolation, OiNK.cd remains closed. Ellis meanwhile is a free man.

The only real loser is the taxpayer. ®