Surveillance footage showing undercover police carrying out a major drugs bust was found in the street.

On the DVDs, undercover officers are seen arresting suspects and searching the grounds of a house.

The film is being used as evidence in a drugs investigation in Brighton and detectives fear if the contents of the discs were made public it could lead to the collapse of a pending court case.

Eleven defendants are due to appear before Lewes Crown Court in May on a string of drug trafficking charges connected with the case.

The discs, which were returned to Sussex Police by The Argus, were found by two passers-by next to a bin near the Sussex Masonic Centre in Queen's Road, Brighton.

One of the women, who did not wish to be named, said: "We were walking to work and they were just lying there next to the bin.

"We noticed them because they were face up and as I walked over I spotted the Sussex Police logo. I thought about giving them back to the police but it would have been hushed up, especially since all the reports of data discs going missing. It needed to be brought to public attention."

Chief Superintendent Kevin Moore, head of Sussex Police CID, said the discs were not lost by Sussex Police.

He said: "These items were categorically served on the defence lawyers. It's not the police that have lost them. It has come via the disclosure process."

As part of the 1996 Criminal Procedure and Investigations Act, police forces are obliged to give defendants and their lawyers access to all information they have gathered during an investigation.

Chief Supt Moore added: "We have had instances where the actual suspects, or defendants, have been in possession of this kind of material.

"Certain material, for instance, could be in the hands of prisoners who are on remand and it could get into other prisoners' hands in the course of that because we have to reveal the evidence and information.

"It's not helpful to us but we have to comply with the rule of evidence."

He said police always kept master copies and on this occasion they had all been accounted for.

Detective Inspector Jason Tingley, part of the investigation, said if the discs were made public, the court case could be jeopardised. He said: "We have no actual control how legal representatives deal with products like this."

Brighton Pavilion MP David Lepper said: "I'm aware of the huge strides the police have made over the last two to three years in Brighton and Hove in dealing with drug offences and anything that jeopardises that work needs investigating.

"I know that police have to disclose evidence to defendants and their representatives.

I was involved in a case about a year ago about gang violence in Churchill Square. That material appeared to be from a CCTV camera and it appeared on YouTube.

"The police response then was: We haven't lost it and we didn't hand it over to them but we have to give copies to defence solicitors.' "If that is what's happened in this case, it is still very worrying that something incredibly sensitive like this appears lying in the street."

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