During a March 2005 bugging operation, 52 tapes were made of conversations which took place in Mohammed Reveshi's car and his Hornby Road, Blackpool, flat.

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He is alleged to have disposed of the body of missing resort teenager Charlene Downes.

During the police operation Reveshi and co-accused Iyad Albattikhi are said by the prosecution to have discussed killing 14-year-old Charlene.

The prosecution and both the defendants' barristers have provided transcripts of what they claim the defendants said on those tapes.

Christopher Mills, a voice recognition expert brought in by Reveshi's defence team, said the fact all transcripts differed so much on their translations made them unreliable sources of evidence.

He added: "There isn't a bit of kit that you can put these tapes into and they provide you with a transcript, it's down to interpretation.

"I presume there will be bits I've got which other people haven't and bits they have which I haven't got.

"There is no machine that you can feed these tapes into and it nicely types it out for you. It's an individual thing.

"The problem with this is you would expect people who work in the industry to have some sort of correlation between transcripts.

Biased

"If two people write out a transcript and they were 95 per cent correlated you could say that the transcript would be fairly reliable.

"I would say the reliability here would be low if you cannot correlate the different versions."

Mr Mills also warned the jury that having a transcript while listening to something tends to make people biased translators.

He added: "I think sometimes when a transcript is in front of you and you're listening you tend to hear what you are reading. We are trained in a way so we can divert that.

"If the quality of what you are listening to is poor you can be influenced by what you are reading."

When asked about Tape 44, in which detectives believed they could hear reference to Charlene's body being put into a mincing machine, Mr Mills said it was the hardest to make out.

He added: "The quality is very low. It caused me the most problems when trying to transcribe it and relate that to other transcriptions."

The jury at Preston Crown Court had previously heard Charlene was murdered after one or both of the men became involved in a sexual relationship with the former St George's High School pupil.

Charlene, of Buchanan Street, Blackpool, has not been seen since November 2003.

Takeaway owner Albattikhi, 30, of Dickson Road, Blackpool, denies murder. Reveshi, 50, has pleaded not guilty to disposing of the body.

(Proceeding)

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