The new tenants at number 48 Forest Edge, a desirable semi in a leafy suburb, soon excited suspicion. At all hours, vans and cars arrived and men carried large cardboard boxes in and out of the house.

Neighbours called the police, who watched the house at Buckhurst Hill, Essex, and decided some sort of pornography operation could be going on. They told the Obscene Publications Squad at Scotland Yard.

The squad obtained a search warrant and raided the house last month. But instead of pornography, they found a video piracy operation. The semi, overlooking Epping Forest, was a factory copying cassettes.

In the front bedroom were racks of video cassette machines, neatly wired up on metal shelving, with fans installed to keep down the temperature. In the second bedroom copied videos, from new releases, such as Rocky 3 and ET, to the Walt Disney classics Pinocchio, The Jungle Book, and Snow White.

The third bedroom contained piles of blank tapes and elsewhere in the house were stacks of cassette boxes with appropriate covers and labels, including the official warnings against breach of copyright. The detectives, who had obtained the warrant under the Obscene Publications Act, had to confine themselves to films they considered might be obscene. They loaded them into their cars, and drove off.

Unknown to them, however, the raid had proved potentially disastrous for other investigators - private detectives hired by a group of video and film companies to crack down on pirates through civil court actions. They had also been watching the house, but were not in position when the police raided it. By the time they turned up later the same day, the house had been completely cleaned out. The hardware and cassettes which had not interested the police had vanished.

"It really upset the apple cart for us," said Norman Abbott, chief executive of the British Videogram Association. "We had had the premises under surveillance for a long time and we thought that with everything gone we would have to start all over again. We have been pursuing pirates like this for a couple of years, using High Court injunctions because the criminal law is so weak, and all our work in this case seemed to have been wasted. The place had been a real Aladdin's cave."

But the investigators stuck to their job and, after days of watching, finally obtained a court order to search a rented van parked in a street near Petticoat Lane. Inside they found 68 video recorders and hundreds of cassette boxes. The person who rented the van, and two other men, last week gave undertakings in the High Court not to deal in counterfeit videos pending further civil court action.

Meanwhile, the police raid has led to a new riddle surrounding the original nasty video, Snuff. In the Forest Edge house the police found more than 150 copies of The Driller Killer - which has since been the subject of a forfeiture order under the Obscene Publications Act in a separate case-and about 50 of Snuff.

This video caused a storm in America after rumours that it had been made with the Mafia and that the killings and mutilations it showed had taken place in reality in front of the camera.

Earlier this year, one British video company, Astra, had bought the rights to Snuff and was about to distribute it here when The Sunday Times exposed the scandal of nasty videos. Astra decided in view of the publicity to withdraw the film, the master was sent back to the US, and no copies have ever been released.

But Snuff is now becoming available throughout the country from pirates, and is on the shelves of some rental shops. Its box hills it as "the original legendary atrocity " and the description on the back asks "Are the killings for real? You are the judges."

The pirate Snuff seized at Forest Edge is now being sent to the Director of Public Prosecutions for possible action under the Obscene Publications Act.

But people buying or renting pirate copies to watch what they are encouraged to believe is real-life violence may have been misled.

A spokesman for Astra said the pirate he has seen is not Snuff at all, but a compilation of various cuts under the Snuff label.

However, these complications are not worrying Detective Chief Superintendent Peter Kruger, operational head of the Obscene publications Squad. "We have not checked to see whether this is the same Snuff or not," he said. "We viewed the material and in our opinion it should be forwarded to the DPP."

By Peter Chippindale

THE SUNDAY TIMES, 12 SEPTEMBER 1982