The highly respected naturalist and broadcaster joined leading scientists in signing an open letter to The Independent on Wednesday, saying it was time to stop funding some potentially painful or cruel types of neuroscience experiments on primates.

The letter, organised by Cruelty Free International, (CFI) formerly the British Union for the Abolition of Vivisection, said there had now been enough progress in human-based alternatives to question the necessity of experiments subjecting primates to fluid deprivation and movement restraint.

Commenting on the letter he had signed, Sir David said: “The recognition that apes, certainly, and to an extent other primates, are so akin to ourselves, and can suffer so much, as we can, has transformed our attitude, or should have transformed our attitude, to using them for our own benefit.

“They are sentient beings that have mental lives comparable to ours, and sensitivities, and pain and deprivation mean things to them, just as they mean things to us.”

Neuroscience researchers, however, have now hit back at his remarks.

The UK Expert Group for Non-Human Primate (NHP) Neuroscience Research criticised the open letter for citing "Non-human primates in neuroscience research: The case against its scientific necessity" - a March 2016 paper written by CFI scientists that appeared in Alternatives to Laboratory Animals, a peer-reviewed journal published by the Fund for the Replacement of Animals in Medical Experiments.

The UK Expert Group said: “We are disappointed to see that David Attenborough and a number of scientists have been misled by the pseudoscience in the paper by CFI, an organisation intent on ending research with all animals, not just primates.

“They have been deceived by the number of animals used in neuroscience procedures, which are a very small proportion of the numbers stated by CFI, and also by the erroneous claim that NHP neuroscience is useless and that recording from seriously ill patients as they are being monitored for surgery is somehow a replacement for research in non-human animals.”

The group’s statement added: “NHP neuroscience is strictly regulated and ethically assessed, and is only used when there are no alternatives. NHP neuroscience has contributed to many advances in medical science benefiting human patients.”

David Attenborough: Life in pictures Show all 35 1 /35 David Attenborough: Life in pictures David Attenborough: Life in pictures 1957 David Attenborough with his three-year-old daughter Susan, as they cover their ears while sulphur-crested cockatoo Georgie lets out a piercing shriek David Attenborough: Life in pictures 1950 David Attenborough with his wife Jane Oriel and older brother and film actor Richard Attenborough at St. Anne's Church, Kew Green David Attenborough: Life in pictures 1955 David Attenborough, holding his son Robert, whilst looking at an animal called a coatimundi, brought home from the combined London Zoo David Attenborough: Life in pictures 1955 David Attenborough and Jack Lester, curator of London Zoo's reptile house, plan their next expedition to British Guiana with the help of Gregory the parrot David Attenborough: Life in pictures 1956 David Attenborough with six-year-old Michael Webb of Kingsbury pets a Capybara after Sir David had lectured to children on the 'Zoological Expedition to British Guiana' at the Royal Geographical Society in Kensington David Attenborough: Life in pictures 1957 David Attenborough, with wildlife photographer Charles Lagus, preparing to depart for New Guinea to make 'Zoo Quest' at London Airport Getty Images David Attenborough: Life in pictures 1958 Prince Charles with his sister Princess Anne meeting Sir David Attenborough and Cocky, the cockatoo brought back from his last Zoo Quest expedition, at the BBC Television Studios in Lime Grove, London David Attenborough: Life in pictures 1961 David Attenborough with two ring-tailed lemurs during a Christmas lecture at London zoo David Attenborough: Life in pictures 1963 David Attenborough with an armadillo from 'Attenborough's Animals' David Attenborough: Life in pictures 1965 David Attenborough after he was appointed the new head of BBC 2 David Attenborough: Life in pictures 1965 David Attenborough and Michael Peacock, Contoller of the BBC, with soft toy versions of Hullabaloo and Custard, the kangaroo mascots which were used as logos for the launch of BBC 2 David Attenborough: Life in pictures 1980 David Attenborough shows Charlie the Llama to schoolboy Patrick Flynn, the millionth child to attend London Zoo's educational lectures and tours David Attenborough: Life in pictures 1982 David Attenborough feeds orangutan David Attenborough: Life in pictures 1985 David Attenborough after being knighted by the Queen at an investiture at Buckingham Palace, London, with his wife Jane (right) and daughter Susan David Attenborough: Life in pictures 1985 David Attenborough signs his book 'the Living Planet' in a Sydney Bookstore in Australia 2004 Getty Images David Attenborough: Life in pictures 1986 David Attenborough with Queen Elizabeth II filming the Christmas Message in the Royal Mews at Buckingham Palace David Attenborough: Life in pictures 1990 David Attenborough poses for a photograph David Attenborough: Life in pictures 1995 David Attenborough watches nature during the filming of Natural Curiosities David Attenborough: Life in pictures 2000 David Attenborough and his wife at the Tate Modern Art Gallery opening party David Attenborough: Life in pictures 2002 David Attenborough with meerkat on his shoulder being filmed for BBC series Life of Mammals David Attenborough: Life in pictures 2003 A python greets Sir David Attenborough during a photo opportunity at Taronga Park Zoo in Sydney, Australia Getty Images David Attenborough: Life in pictures 2003 Sir David Attenborough holds a baby salt water crocodile during a photo opportunity at Taronga Park Zoo in Sydney, Australia Getty Images David Attenborough: Life in pictures 2005 David Attenborough poses with The Swan Hellenic Oldie of the Year Award at the 'Oldie Of The Year Awards' honouring veteran notables together with Britain's oldest celebrity superstars, at Simpsons in the Strand in London. Sir David Attenborough was announced as the Swan Hellenic Oldie of the Year at the 13th annual awards Getty Images David Attenborough: Life in pictures 2005 David Attenborough plants a Wollemei Pine at Kew Gardens in London Getty Images David Attenborough: Life in pictures 2005 David Attenborough signs copies of his latest publication Life In The Undergrowth, published in relation to the BBC One series, at the Natural History Museum in London Getty Images David Attenborough: Life in pictures 2006 Sir David Attenborough and Lord Richard Attenborough robe up, before they are awarded the title of Distinguished Honorary Fellowships from the University of Leicester at De Montfort Hall in Leicester Getty Images David Attenborough: Life in pictures 2007 Sir David Attenborough launches National Moth Recording Scheme at London Zoo in London Getty Images David Attenborough: Life in pictures 2008 Sir David Attenborough sits in The Queen's Gallery, Buckingham Palace in the Amazing Rare Things exhibition in London Getty Images David Attenborough: Life in pictures 2009 Prince William, Dr Michael Dixon and Sir David Attenborough host the opening of the The New Darwin Centre at The Natural History Museum in London Getty Images David Attenborough: Life in pictures 2011 Britain's Queen Elizabeth II speaks with naturalist David Attenborough during a special exhibition of artefacts from the Royal Collection and Royal Archives at Buckingham Palace in London Getty Images David Attenborough: Life in pictures 2011 Sir David Attenborough with the Specialist Factual award at the Philips British Academy Television Awards at the Grosvenor House in London David Attenborough: Life in pictures 2012 Sir David Attenborough poses with a floral sculpture of himself outside the Royal Botanical Gardens at Kew Gardens in London Getty Images David Attenborough: Life in pictures 2012 Sir David Attenborough at the UKTV Showcase held at the Saatchi Gallery in west London David Attenborough: Life in pictures 2013 David Attenborough during the filming of "Micro Monsters with David Attenborough," a series about insects David Attenborough: Life in pictures 2016 Sir David Attenborough attends the launch of the London Wildlife Trust's new Flagship nature reserve Woodberry Wetlands in London Getty Images

Other scientists backed the expert group’s criticism, while avoiding mentioning Sir David by name.

Roger Lemon, Professor Emeritus at University College London, who last year won the Fyssen International Prize for his work on neurocognitive mechanisms, insisted: “Non-human primate research contributes fundamental knowledge about how the primate brain functions.

“It has made, and continues to make, an essential contribution to research leading to the treatment of debilitating movement disorders such as Parkinson’s disease, as well as to other forms of neurodegenerative disease.

“To state otherwise, as CFI have done, is ignoring the long history of animal research in the fight against disease.”

Dr John Isaac, Head of Neuroscience and Mental Health at Wellcome, the charity which offers funding to researchers, insisted that rigorous criteria had to be met before money could be provided for experiments on any type of animal.

He said: “We only fund research involving any type of animal where there is no alternative, and where the benefits, either scientific or directly for human or animal health, outweigh the impact on the animals.”

Dr Isaac added: “Non-human primate research is essential for understanding more about the brain and neurological diseases that affect it, for example Parkinson’s disease and Alzheimer’s disease. This is because certain important aspects of human brain function cannot be replicated by any other means. Non-human primate research is also crucial for testing whether new medicines, including vaccines, are safe and effective.”

The criticism was rejected by Sarah Kite, the director of special projects at Cruelty Free International, who told The Independent: “Sadly, yet again those defending primate research have chosen to attack other scientists instead of having an informed and intelligent debate about the future of primate research in the UK. This is a hugely controversial area of research with profound ethical and moral concerns, and increasingly scientific concerns, about subjecting non-human primates to such substantial levels of suffering - suffering that can involve invasive brain surgery, water deprivation, physical coercion and physical restraint.

“No attack on any scientist’s credibility can detract from the profound sense of unease there is among many in the scientific community, let alone the public, in using non-human primates in experiments.

“The extensive review of primate research (Non-human Primates in Neuroscience Research: The Case Against its Scientific Necessity) concluded that neuroscience research would be more relevant to and successful for humans should it be conducted with a human focus rather than the continued use of primates.

“In particular, the review concluded: neuroscience experiments on monkeys are of only speculative value to humans; data collected from monkeys used in neuroscience research are misleading and of poor relevance to people due to the important differences between primates and humans in brain structure and function; the significance of results from ethical neuroscience research in humans is being underestimated by researchers.”

Sir David was also backed in his criticism of experiments that deprived primates of water and restricted movement by Dame Jane Goodall, who is considered one of the world’s foremost experts on chimpanzees after spending 55 years studying them in the wild in Tanzania.

She said: “To confine these primate relatives of ours to laboratory cages and subject them to experiments that are often distressing and painful is, in my opinion, morally wrong.

“To restrain their movement and deprive them of water is inhumane and extremely cruel and we have no right to exploit them in this way for any reason.”

Responding to the letter signed by Sir David, a spokesperson for the Medical Research Council, which funds some primate testing, said the licensing process for such experiments was “robust”.