One of the men behind the Hatton Garden raid claims he has offered to tell police where his share of the haul is hidden but that detectives have ignored him.
Daniel Jones made the revelation in a letter to a reporter, adding it is possible the loot could be discovered by someone else if he is not allowed to disclose its location.
The 58-year-old has admitted his part in the burglary and wants to be taken out of his high security Belmarsh prison cell so he can return what he stole.
Jones wrote to Sky News reporter Martin Brunt from behind bars, saying: "I've instructed my solicitor...to tell the police Flying Squad that I want to give back my share of (the) Hatton Garden burglary, they said it's in motion.
"I now understand that the police said that the prison Belmarsh won't release me to the police. What a load of bull.
"The police can't want it back, as I'm the only person in the world to no (know) where it is, deep down. I want to do the right thing and give it back."
He also referred to himself as a "burnt-out burglar", suggesting detectives were scared of taking him out of prison because they feared he would have get a "hit-squad" to break him out.
Responding to the claims, a Scotland Yard spokesman said: "We are not prepared to discuss an ongoing investigation."
Jones and three other men pleaded guilty to conspiracy to burgle Hatton Garden Safe Deposit over between April 1 and April 7 this year. They are all awaiting sentence.
Five other men deny the offence and are due to stand trial at Woolwich Crown Court next month.
The raid over the Easter weekend saw thieves break into the vault in London's diamond district, after using a drill to bore a hole 20in deep, 10in high and 18in into the vault wall.
Once inside, the thieves ransacked 73 safety deposit boxes, taking goods in excess of £10 million.