Professor David Nutt has been no stranger to controversy over the years. So the psychiatrist and former Government drugs tsar, will not have been fazed when he raised eyebrows recently by drawing a parallel between the repression of research into the effects of psychedelic drugs like LSD with the censorship of Galileo and the banning of the telescope.

“It has been the great unanswered question in neuroscience,” he argues. “What is the nature of the profound psychedelic experience that LSD produces, with long-lasting changes in the way people view themselves and the world around them?”

Now, he believes, scientists are coming close to an answer.His team at Imperial College London, having overcome numerous regulatory hurdles, are the first in the world to scan the brains of volunteers under the influence of LSD. Professor Nutt announced this week they would need to crowd-fund £25,000 to pay for an analysis of the findings, after funding sources dried up. Not following through on their work, he believes, would be a tragedy.

He and a growing number of scientists around the world are beginning to revive interest in LSD as a medicine: for addiction, for obsessive-compulsive disorder (OCD), and for post-traumatic stress disorder (PTSD). It could even, some believe, help alleviate the anxiety felt by terminally ill people at the end of their life.

A trip through time: The history of LSD Show all 5 1 /5 A trip through time: The history of LSD A trip through time: The history of LSD 19 April 1943 Having accidentally ingested LSD three days earlier, Albert Hofmann takes the world's first intentional acid trip and rides home from the lab on his bike. The event is commemorated annually on "Bicycle Day" AFP/Getty Images A trip through time: The history of LSD May 1950 The first article about LSD appears in the American Journal of Psychiatry A trip through time: The history of LSD 22 November 1963 Aldous Huxley, author of The Doors of Perception, instructs his wife to administer him with LSD on his deathbed, and passes away "very, very gently" AP A trip through time: The history of LSD April 1965 The Beatles are introduced to acid by George's dentist. Sgt. Pepper's Lonely Hearts Club Band comes out in June 1967, and while John denies "Lucy in the Sky with Diamonds" was an intentional expansion of "LSD", few believe him Rex Features A trip through time: The history of LSD 14 January 1967 Four years after he is sacked from the psychology department at Harvard, acid evangelist Dr Timothy Leary tells a 30,000-strong gathering at the Human Be-In in San Francisco to, "Turn on, tune in, drop out" Getty Images

“People are very, very frightened of dying. They see it as the end. On psychedelics, this sense of self begins to break down,” says Professor Nutt.

“People in the psychedelic trip often experience being at one with the world or even with the universe. It’s as if they have died, as if they’ve gone out to another place. They exist beyond their body. That experience can give them a sense of perpetuity, of permanence, of being part of the cycle of life, which of course we all are.”

A recent study in Switzerland has already looked at the use of LSD for this purpose. After two months, a small number of terminally ill patients given doses of LSD in sessions with a psychiatrist experienced improvements in their anxiety levels – findings which persisted for a year among those who survived.

Professor Nutt thinks using LSD in this way, strictly on a voluntary basis, should be further investigated. It is, after all, how the most famous exponent of psychedelics, the author Aldous Huxley, ushered in his own eternal rest.

“The way we deal with death is to poison people with opiates so that they can’t think,” Professor Nutt says. “They’re pain-free but they’re constipated, can’t speak, and are numbed before they die. I think the idea that there might be an alternative strategy is something we should at least explore.”

Professor David Nutt appeared discussed his 'harm index', which in 2010 ranked alcohol as three times more harmful than cannabis

Professor Nutt is one of the leading figures in a recent renaissance of interest in psychedelic drugs. In the 1950s and 1960s, hundreds of studies were carried out into these substances, and LSD – then legal – was tested as a treatment for alcoholism, depression, and as end-of-life therapy.

Then came the wide-scale, counter-culture use of psychedelics as recreational drugs, quickly followed by criminalisation. Research into them was, if not banned, regulated almost out of existence.

It is these missing decades that so frustrate Professor Nutt, who says that scientists are only just catching up with “50 years of censorship”.

Exactly how the psychedelic trip can lead to long-term benefits in a person’s thinking is one of the mysteries scientists hope to uncover.

“Our work with psilocybin [the magic mushroom compound] points to a circuit in the brain called the default mode –where your persona and your ego lies. When you’re sitting, relaxing, thinking about yourself, your past, your future, your family – that’s the default mode. In addictions and depression and OCD that can become disorganised and locked on to different targets. It gets locked into thinking negative thoughts, or craving thoughts. We think that [psychedelics] could well unlock that, and break that terrible habit of thinking inappropriately and let you go back to thinking normally again.”

Recreational use of the drug influenced the likes of Jimi Hendrix (Getty) (Hulton Archive/Getty)

Since being dismissed as chair of the Government’s Advisory Council on the Misuse of Drugs in 2009, after saying that ecstasy, cannabis and LSD were less dangerous than alcohol and tobacco, Professor Nutt has maintained a high profile, taking part in Channel 4’s Drugs Live, in which volunteers have been filmed taking illegal substances, and the effects on the brain are explained by himself and other scientists.

Criminalisation of drugs, while appropriate for the most dangerous substances like heroin and crack, has been wholly counterproductive at the less harmful end of the spectrum, Professor Nutt argues.

Skunk, a high-strength variety of cannabis, which was recently shown to be responsible for one in four new cases of psychosis in a recent King’s College London study, has become common, Professor Nutt believes, as a direct result of criminalisation: pushed by black market dealers who in a decriminalised system would lose their monopoly.

“We need to accept the fact that most people like to change the way they feel,” Professor Nutt said. “Most people use alcohol. My view is that any drug that is less harmful than alcohol should be made available in some kind of regulated fashion because that will reduce the harms of alcohol.”

Drug reform is back on the agenda after Nick Clegg announced this week that the Liberal Democrats manifesto would include proposals to soften penalties for drug users. Professor Nutt said the party should be willing to use the issue as a deal-breaker in any coalition negotiations that may follow the election.

“The drug laws are some of the most archaic and corrupt laws present in this country,” he said. “They destroy lives through criminalisation and they really impede medical research. We deal with drugs in a pre-Victorian fashion. We need to move into the 21st century.”

Acid test: The dope on LSD

First synthesised by Swiss scientist Alfred Hofmann in 1938, in its early years lysergic acid diethylamide (LSD) was relatively easy to come by.

Between 1953 and 1973, the US government spent $4m (£2.66m) on 160 studies involving LSD to determine its medicinal value and its effects on creativity and spirituality. Participants regularly had very positive experiences.

By the 1960s advocates of LSD included Aldous Huxley and Timothy Leary, who popularised the “turn on, tune in, drop out” philosophy of a 1960s counter-culture that was defined by the psychedelic (meaning “to manifest the soul”) experience.

The imagery and ethos of psychedelia, and the recreational use of the drug, soon spread throughout the western world, influencing art and music. The Beatles experimented with it, although probably not as much as some suggest, and The Doors and Jimi Hendrix also combined LSD use with the creative process.