London - The woman volunteer thought Nim was coming to hug her, but instead the young chimp lunged, biting so deep into her cheek that his fangs pierced her mouth.

As she clutched her bleeding face, the little ape was beside himself, using the same piece of sign language again and again to attract her attention. “I’m sorry, I’m sorry,” he repeated.

This haunting recollection is one of many contained in a riveting new film, Project Nim, by the director of the Oscar-winning Man On Wire, about one of the most bizarre scientific experiments of recent times.

British film-maker James Marsh’s latest subject undertakes a journey every bit as astonishing as tightrope artist Philippe Petit’s walk on a wire strung between the Twin Towers of New York’s World Trade Centre.

Nim was a chimp that was raised as a human child in order to test out the radical theory that man and his closest relative could learn to talk to each other.

Tragically, as Marsh’s film relates through a mixture of archive footage, re-enactments and interviews with those who took part in the early-Seventies experiment, this is a tale that ultimately says more about human arrogance than simian intelligence.

For those who have been charmed by the recent tale of Digit, the gentle adult gorilla that shares the marital bed of the devoted French couple who look after him, here is a much darker side to man’s attempts to bond with his ape cousins.

A helpless pawn ripped - quite literally - from his mother’s breast, Nim was a victim of the naive, hippy- culture-infused world of early-Seventies New York. He fell into the clutches of a hapless band of woolly social scientists who gave him human clothes, human food and enough doting young lady volunteers to send his simian hormones haywire. If it were not for what happened later, it could have been a Woody Allen comedy.

Project Nim began in November 1973 with Nim’s birth at a primate research centre in Oklahoma. He spent just a few days in the arms of his real mother before she was knocked out with a tranquilliser dart and her screaming baby was handed straight to his delighted new, human, mother.

Nim had been selected by Herb Terrace, an ambitious psychology expert at New York’s Columbia University, to prove a premise that was “way out” even for the Seventies: that a chimp raised as a human and taught sign language could learn to communicate in grammatical sentences. Finally, man might understand what animals were thinking - and perhaps vice versa.

Terrace, a small, mustachioed man with a huge ego, had named the little creature Nim Chimpsky - a pun on Noam Chomsky, the famous thinker who insisted that only humans have the capacity for language

However, Terrace thought differently and had chosen Stephanie LaFarge, a former student and lover, to bring up Nim in the large Manhattan townhouse she shared with her self-confessed “rich hippy” writer husband, Wer, and their seven children.

But it was a disastrous decision - Stephanie never bothered trying to discipline Nim. She did not take any notes on the experiment and did not keep a log of Nim’s progress, but she did breastfeed him and give him alcohol and puffs on her cannabis joints.

He was encouraged to lay waste to their expensive home and wind up his rival for her affections, Stephanie’s husband. Home movie footage shows the little creature, a blur of black and white in his romper suit, charging around as Stephanie recounts dreamily how she let him explore her naked body as he moved into puberty.

“I never felt sexually engaged with him,” she recalls, which is a blessing at least. Yes, it certainly was the Seventies.

The snapshots of those halcyon early days would grace any family album - baby having a nap, playing with the cat, trying out the lavatory (with sporadic success) or simply staring adoringly into the smitten eyes of the women who queued up to cuddle him.

Chimp throats cannot reproduce human speech, so the idea was to teach him sign language. “Drink” was the first sign he learned, followed by “eat”, Ôme”, Ô”im” and “hug”. Volunteer Jenny Lee remembers his heart-warming empathy. “Whenever you were upset he would come over and sit with you and kiss the tears away,” she says.

But it didn’t last. Laura-Ann Petitto, a pretty Columbia researcher recruited to the project, recalls turning up at the house to find “utter chaos”. She was particularly appalled to find Stephanie fixated by Nim’s penchant for what is delicately known as self-abuse.

Finally, realising things had gone awry, Terrace moved Nim to a big empty house in the suburbs where Laura-Ann became his new “mum” and the band of helpers swelled.

By now, the chimp was becoming famous. New York magazine put him on its front cover in 1975 under the headline “First Message From The Planet of the Apes” and he was filmed for the children’s TV show Sesame Street. He now knew the hand signs for words such as “napkin” and “dress”.

The publicity-hungry Terrace rejoiced - “I had a chimpanzee who was making history” - but Nim was also getting bigger and more aggressive. If any of “his people” showed the slightest signs of vulnerability - even just accidentally turning their back to him too quickly - the hair would rise on his arms and, Laura-Ann recalls, he’d “go into attack...he had to draw blood”. She still has the scars, running down her arms, to prove it.

Nevertheless, in his own way, Nim was devoted to her - and very jealous of her affections. Laura-Ann had begun an affair with Terrace and one day, as she packed up to leave after a language session with Nim, the chimp showed what he thought of her disloyalty.

Jumping 25ft from a second-floor window, he grabbed his favourite female and started pounding her head into the pavement. It took four men to get him off.

“He wasn’t my child, he wasn’t my baby,”: she said in the film, her voice still quivering at the memory. “You can’t give human nurture to an animal that could kill you.”

But still the gallant band behind the experiment persevered. Renee Falitz, a small but plucky professional sign language teacher, became Nim’s new mother figure until he one day sank his fangs deep into her cheek. When Nim was finally allowed to see her again and immediately reached for her face, she was off. “It was like breaking up with a bad boyfriend,” she recalls.

By now, it was clear that someone was going to get seriously hurt before too long. Much to the disgust of his underlings, Herb Terrace flew Nim back to the Oklahoma research centre where he had got him fewer than four years earlier.

Their voices breaking with emotion, Nim’s carers described the moment he saw his new home - a cage full of other chimps staring blankly at him. “I thought ‘Holy s***!’ and knew Nim did too,” recalls Joyce Butler. “He’d never seen a chimp before and he was holding on tight to me.”

As his family walked away, leaving him bewildered and surrounded by chimpanzees he was terrified of, Nim desperately made the sign which meant “hug me”.

Of course, this in itself might seem poignant proof that Terrace’s experiment had succeeded. However, Terrace had analysed the data and had decided he had been wrong. Chimps couldn’t use language, after all. Nim had simply learnt to mimic the signs his teachers made in order to beg for things.

“So he wasn’t trying to say ‘You have a beautiful cat over there’. He was saying ‘I want it’,” said Terrace.

The good doctor visited Nim once in Oklahoma and that was it. But at least Nim had the devotion of a local volunteer and diehard hippy, Bob Ingersoll. They went on walks and, having exchanged the relevant hand signs - “Smoke”, “Now” - they’d often share a cannabis joint when nobody was looking. “He liked to have fun - who doesn’t,” Bob reminisces.

Unfortunately for Nim, the drugs were to get a lot worse than cannabis. In 1982, he and most of the other chimps were sold by their hard-up owner to a medical research laboratory for Aids and hepatitis vaccine experiments.

In one of the most harrowing moments of the film, former lab staff recall the moment they realised that a few of the creatures - apparently led by Nim - were frantically using sign language to communicate with them through the bars of their tiny cages.

Nim would almost certainly have died there, had his life not taken another improbable turn.

Harry Hermann, a resourceful lawyer and animal rights activist, had him freed after arguing that a chimp that had been raised as a human had a right to plead its case in court like a human. Desperate to avoid his court turning into a circus, a judge agreed.

Nim spent his final years at an animal sanctuary in Texas, safe from abuse if not boredom, as its sole chimp. Other chimps joined him eventually, but witnesses said he still preferred people right until the end.

Yet he was not always easy company. When Stephanie LaFarge - his first human mother - went to visit, swanning into his cage against the warnings of staff, Nim grabbed her by the ankle and dragged her along the ground “like a rag doll”.

Just as staff were about to shoot him, he stopped. He had made his point and put her in her place, Stephanie now understands. “We had done so much damage removing him from what his life should have was wrong, wrong,” she said. A bit of wisdom at last, but it was far too late.

Nim expired a few years later, in 2000, of a heart attack, minutes after signalling “hurry” to the volunteer making his breakfast. He was just 26 - tragically young for chimps, which will normally live to 60 in captivity.

Stephanie was the only member of the Project Nim team who attended his memorial service. Terrace, portrayed as a sort of heartless Dr Doolittle in the film, still largely stands by his ghastly experiment.

“The project’s major fault was that it didn’t have an exit strategy,” he tells me, matter-of-factly. He had never experienced chimps becoming aggressive, he said, so had never planned what to do with Nim if he got like that.

The last words in the documentary come from a kind-hearted vet at the chimps’ animal testing lab, one Dr Mahoney. “Chimps are very forgiving,” he says ruefully. “They’ll forgive you.”

After the way they treated Nim, that’s very much open to doubt. - Daily Mail