THE voice expert who analysed the Wearside Jack tape said last night that he had written to police in 1979, warning the West Yorkshire force that the tape was a hoax.

Stanley Ellis, who was teaching phonetics at Leeds University at the time of the Ripper inquiry, spent months analysing the tape.

Without any strong leads, senior police officers at the time virtually ruled out any suspect who did not have a Wearside accent.

But Mr Ellis said he and colleague Jack Windsor Lewis, who analysed the letters sent by the hoaxer, both believed the letters and tape were not sent by the Ripper.

They expressed their concerns to Detective Superintendent Richard Holland, who was in overall command of the Ripper inquiry.

"We began to feel that they were clearing people who could be guilty, so we both wrote in 1979 saying we felt the letters and the tape were not genuine, but they didn't agree with us," said Mr Ellis, 79, of Harrogate, North Yorkshire.

"There was never any evidence in the letters or on the tape that the speaker was involved with the murders, and all the information in the letters was in the public domain."

At the time, Mr Ellis travelled frequently to Sunderland with police to take recordings to pinpoint the accent.

He said: "I eventually came to the conclusion that the nearest voice was from Southwick or Castletown."

Mr Ellis said he had been called to investigate dozens of hoax calls over the years of the Ripper inquiry.