Mr Bleach stands trial next month in Calcutta, accused of "waging war against India". If convicted, he could face execution. But for now, authorities want the Yorkshireman alive so that he can testify against some of his 12 co-conspirators - leaders of a powerful, militant Hindu sect called the Ananda Marg, whose orange-robed followers advocate the eradication of state governments and have a ritual dance with human skulls.
The prisoner's every meal, invariably rice, chapattis and curried vegetables, is also tested for poison before the food tray is slid into his solitary cell, according to jail officials.
The tale of how this son of a parish councillor ended up in a Calcutta prison, hunted by assassins and charged with treason, began early last year. Mr Bleach, who runs a defence sales firm, was approached in Britain by an intense man with a wispy beard calling himself Kim Davy. The New Zealand passport he carried later proved to be a forgery, and detectives claim that Davy - who might be British, they say - was not a mercenary or arms smuggler, but a militant within the Ananda Marg.
Founded by an ex-railway clerk, P R Sarkar, to spread "inner discovery and social activism", the sect ran foul of West Bengal's Communist government, and Sarkar (who went by the title He Who Attracts Others As The Embodiment of Bliss) was jailed in 1971 for seven years without trial. Later the Ananda Marg was accused of trying to shoot the state's Marxist chief minister, Jyoti Basu.
Persecution of the Ananda Marg climaxed in 1982, when Communist thugs began spreading rumours in Calcutta that sect members were stealing children. A mob grabbed 17 Ananda Marg nuns and lynched them on a bridge. "They have killed dozens of us because we refute Marxism," said one bearded Ananda Marg monk at their Calcutta headquarters. Officials also banned the sect from using human skulls in worship to Lord Shiva, the god whose terrible dance can destroy the world.
The torment inflicted on the Ananda Marg has strengthened its members' conviction - one shared by such extremist cults as the Branch Davidians of Waco, Texas and Aum Shinri Kyo of Japan - that the world needs to be cleansed by an Armageddon, and that they are the chosen few destined to survive.
Indian police are certain that Mr Bleach was never a member of the Ananda Marg, which has branches and schools in Britain. "He's outspoken and clever, but very guarded during interrogation," said one police detective. An ex-British military officer who lived alone in a house on the North Yorks moors, Mr Bleach was known by locals for his odd gardening habits: he was once spotted mowing his lawn at night. In a photograph taken during his arrest, Mr Bleach appears to be thin and handsome in a hawkish way.
The meeting with the mysterious Mr Davy set off a chain of events that culminated in the Yorkshireman finding himself, on the night of 17 December 1995, aboard a chartered Russian Antonov cargo plane with his client and an aircrew of five Latvians, none of whom spoke any English. After taking off in Karachi, the flight meandered over northern India, stopping in Benares for refuelling before heading to Calcutta. Around midnight, the cargo plane is alleged to have parachuted several crates of arms into the rocky hills of Purulia, in West Bihar, not far from the Ananda Marg's so-called world headquarters.
The crates contained enough weapons to trigger off an insurrection: 240 assault rifles, 10 rocket launchers, 81 anti-tank grenades and more than 20,000 rounds of ammunition. As one police investigator commented, "If you're going to have a world government, you need guns. The men in power are not going to step down."
By coincidence, a jeep from the Ananda Marg ashram had run over a tribal girl near Purulia, and the angry crowd gathered on the road beside the dead girl's body was there to witness the lethal cargo drifting down. The police were eventually informed, after the tribesmen opened the crates and looted a few guns.
Then, inexplicably, the cargo plane spent the next four days criss-crossing India before its erratic behaviour was spotted by an Indian airforce radar operator in Madras. On 22 December the Antonov was forced down at Bombay airport.
A security lapse enabled the quick-witted Mr Davy to escape. He hitched a ride with airport officials from the plane to the terminal, and vanished into Bombay's teeming streets. The Hindi-speaking Mr Davy, whoever he was, has never been found. Police intelligence claim he was spirited out of India by the Ananda Marg. "They are trying to hide this Kim Davy somewhere in the world. Let them try it," said one detective. "With the help of Interpol, we'll find him."
Mr Davy left his suitcase behind on the plane, which police said contained proof linking him directly to the Ananda Marg. Inside was a navigational device set to Purulia, where the arms had fallen, along with a photograph of a smiling Mr Davy posing with an Ananda Marg devotee.
In raids on 40 Ananda Marg retreats across India, police claim to have discovered computer discs giving evidence that the arms were meant for the Ananda Marg. Several of the sect's leaders have been arrested, also on sedition charges, but at least six other senior Ananda Marg monks are still being hunted. "They are not in hiding. They are sannyasis - wandering monks," said one spokesman at the sect's Calcutta office.
Mr Bleach's routine in the Presidency Jail, built by the British for captured Indian freedom fighters, is one of unending tedium. He sits alone in a dark 12ft by 10ft cell, forbidden even to have a radio. He has been visited only by his police interrogators and a diplomat from the British consular office in Calcutta. Because of the severity of the charges against him, Indian lawyers are reluctant to handle his case. With the trial only weeks away, the Briton has yet to see the official charge sheet against him, running to more than 300 pages, and yet, against all odds, he has decided to defend himself.
Some Indian newspapers claim that Mr Bleach may be turning state evidence against the Ananda Marg, but police officials denied this. Some newspapers reported that British intelligence might have tipped off their Indian counterparts of the intended arms drop in Purulia, and if so, Mr Bleach, with his old military connections, might have been the source. That, according to legal experts, could be his only hope of saving himself from either the death penalty or a life spent in an Indian jail.