A mystery suspect in the multimillion-pound Hatton Garden raid is an ex-policeman, it has been claimed.
The thief known as "Basil" was also the brains behind the £14 million heist, according to a letter written by fellow gang member Danny Jones to Sky News.
Last month the Metropolitan Police's Flying Squad issued an urgent public appeal for help in tracing Basil and the missing two thirds of the loot, which included gold, diamonds and sapphires.
In excerpts from the letter published by Sky, Jones, 60, who is at Belmarsh Prison awaiting sentencing, wrote: "I can say that someone told me he (Basil) was an ex-policeman who got into security by the guy who introduced him to me.
"He said Basil heard about me from a close friend on the police force, as I was arrested for a similar raid in Bond Street in 2010."
He added: "Basil was the brains, as I was recruited by him. He let me in on the night of the burglary, he hid keys and codes throughout the building."
Jones went on to say he did not know Basil's real identity, and if he did he would not tell as "it's not a done thing where I come from".
Scotland Yard declined to comment on the claims.
In January three men were found guilty of being involved in the raid, which took place over the Easter weekend last year and is believed to be the biggest burglary in British history.
Carl Wood, 58, and William Lincoln, 60, were convicted of conspiracy to commit burglary and conspiracy to conceal, convert or transfer criminal property, while plumber Hugh Doyle, 48, was found guilty of concealing, converting or transferring criminal property between January 1 and May 19 last year.
They were members of the gang, including five others, who ransacked 73 boxes at Hatton Garden Safety Deposit in central London after using a drill to bore a hole into the vault wall.
Ringleaders John "Kenny" Collins, 75, Jones, Terry Perkins, 67, and the group's oldest member Brian Reader, 76, pleaded guilty to conspiracy to commit burglary in September.
Collins, of Bletsoe Walk, Islington; Jones, of Park Avenue, Enfield; Perkins, of Heene Road, Enfield, and Reader, of Dartford Road, Dartford, have been in custody since their arrests.
They are due to be sentenced along with Wood, of Elderbeck Close, Cheshunt, Hertfordshire, Lincoln, of Winkley Street, Bethnal Green, east London, and Doyle, of Riverside Gardens, Enfield, north London, on March 7.