Yates: Handled stolen machine

Following the theft Miss Large received letters and phone calls threatening that the machine would be destroyed unless a �25,000 ransom was paid.

Miss Large, who became Bletchley Park Trust's director in 1998, said she suffered medical problems due to the stress of the alleged blackmail.

In court, Yates admitted sending the majority of the letters and making the phone calls while disguising his voice.

Miss Large said: "I had to fight for what was right and not be cowed or given in to the kind of behaviour that was demonstrated by Mr Yates."

Secrecy tradition

"In keeping with the traditions of Bletchley Park I couldn't talk to my colleagues or to the trustees," she said.

"Except for a handful of police, I had to keep it to myself. It was an incredibly stressful time."

Miss Large also paid tribute to the combined efforts of police forces who helped bring the case to a successful conclusion.

She said: "The result in the Enigma blackmail trial proves the strength of the prosecution's evidence.

The device was sent to Jeremy Paxman

"It is a result for people around the world who deplored this act of historic vandalism.

"The police, the national crime squad and other agencies involved deserve the highest praise for securing a successful conclusion to this chapter of Enigma."

Bletchley Park, code-named Station X during World War II, housed 10,000 linguists, mathematicians and chess experts attempting to break the Enigma code, used by the Nazis to encrypt top secret messages between their forces.

Work there was credited with shortening the conflict by several years and so saving thousands of lives.

Displayed again

Following the months of ransom demands, the machine was eventually sent to BBC Newsnight presenter Jeremy Paxton, minus three rotor wheels vital to its use.

Further demands for the �25,000 were then received for the money to be placed in a graveyard in �50 notes in the village of Longford, Derbyshire, or else the the rotors would be destroyed.

The rotor wheels were later returned safely.

The machine was on again on display at Bletchley Park on Wednesday.

Case open

Yates was arrested last year and insisted he was merely a go-between acting for a client known as 'the master' who was living in India.

Detectives have failed to trace the supposed purchaser, or the actual thief of the machine.

Police, who remain convinced that inside information was used to steal the Enigma, said the case remained open and although Yates had been prosecuted their enquiries were far from closed.

Yates was granted bail and the case has been adjourned until 19 October for pre-sentence reports.