The characters could have been lifted from an airport thriller. On one side stands a moneyed intellectual who ditched a career in chartered accountancy in London to lead a cadre of ruthless Maoist rebels in the jungles of India for 30 years. On the other is a Government now intent on injecting him with a truth serum to force him to betray his comrades.

When Kobad Ghandy was captured in Delhi in September, the authorities claimed that he was the highest-ranking member of India’s long-running Maoist — or Naxalite — insurgency to be taken alive.

Last week a Delhi court gave police permission to conduct “narcoanalysis” — the use of psychoactive drugs — on Mr Ghandy in an attempt to extract the secrets of a movement that claims to be battling for justice for India’s oppressed underclass, but which has killed more than 2,500 people in the past three years.

The controversial procedure — which has been blocked for the time being by another court — would probably have involved Mr Ghandy, who is in his early 60s and quite seriously unwell, being injected with the barbiturate sodium pentothal through a drip. Once the drug had lulled him into a trance-like state, the Maoist leader — an upper-class ideologue from a wealthy Mumbai family who was seduced by leftist agitprop as a student in London — would have been questioned.

Theoretically, because lying involves more complex brain functions than telling the truth, the suppression of “higher” brain functions in this way can lay bare the “truth”. The evidence is inadmissible in Indian courts, but the nation's police regularly insist that it is invaluable in establishing facts.

In reality, however, the dubious legality and efficacy of the procedure might stand as emblematic of India’s broader efforts to stamp out the Naxalite threat.

Truth serums were often employed by Western intelligence agencies during the Cold War, before it emerged that they often induced hallucinations, delusions and psychotic behaviour. While drugs can make subjects more talkative, a subject with a firmly entrenched false story embedded in his mind can still lie. Inquisitors also found that dosed subjects often freely mixed fact with fantasy.

Now widely discredited, truth serums are banned in Britain, where the use of a needle on a prisoner would arguably constitute assault, and in most other democratic states: although some operators believe that they should be used in terrorist cases — while others reckon they probably still are.

Moreover, the Indian Government’s efforts to drug Mr Ghandy may prove controversial beyond the question of the reliability of the information the procedure might have extracted. A source with knowledge of the events leading to his capture in Delhi says that the Maoist leader had surfaced only after forging a deal with the authorities to leave behind his underground life to receive medical care. The Government reneged on this deal and took him into custody, the source said. “The authorities turned it into a media circus,” the source added.

That version of events has a certain logic to it: it currently suits the Indian Government, shaken by a recent increase in Naxalite violence, to appear tough on the Maoists’ ringleaders — even one such as Mr Ghandy, who was in charge of propaganda and probably has little useful information on the rebels’ military wing.

In July three Maoist attacks in the northern state of Chhattisgarh left 36 policemen dead. The rebels, who want nothing less than to foment a revolution, have a long record of pulling off such audacious operations: in 2005, more than 1,000 Maoists attacked a jail in the district of Jehanabad and freed 340 prisoners.

Attacks have become more frequent in recent weeks. Last month Maoist cadres beheaded a police inspector in Jharkhand; killed 17 policemen in an attack in Maharashtra; kidnapped a police inspector in West Bengal; and hijacked a Delhi-bound train.

The Indian Prime Minister repeated his view that Naxals — who are estimated to have as many as 20,000 troops — represent the greatest internal threat to the country’s security.

That does not seem an exaggeration: according to the Government’s own estimate Naxalite cadres are active in 23 of India’s 28 states. The militants’ goal is to “liberate and control” a third of the country by the end of this year, a report from the Home Ministry said. The same document said that there were 39 leftist extreme groups operating in India — whose combined armed wings number an astonishing 100,000 men and women.

The Government recently launched Operation Green Hunt — a large deployment of national paramilitary forces and state police forces to end armed resistance by the Naxalites and to secure areas that had been under rebel control.

The fear now is that a clumsy strategy will undermine these military operations.

Human Rights Watch (HRW) and others have documented widespread abuses by Indian government forces engaged in past anti-Naxalite drives, including arbitrary arrests, torture, and unlawful killings — all of them unpunished. In Chhattisgarh, the state government has backed the Salwa Judum, a vigilante movement, “leading to killings, rapes, and the forced displacement of tens of thousands of civilians”, according to HRW.

This is not to excuse the Naxalites, who frequently brutalise the poor oppressed villagers they claim to be fighting for. But if the Indian Government wants to end the Maoist menace, it needs to win the hearts and minds of those who are being recruited by them — the same poor villagers. That will require development work to improve rural infrastructure and to create effective social safety nets. And that’s the truth.

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