David Nutt, professor of neuropsychopharmacology at Imperial College London, told The Sunday Times that bankers' cocaine habits were to blame for the recent financial crisis as well as the 1995 collapse of Barings Bank.
Nutt said the drug made the bankers "overconfident" and prone to taking more risks. He said the cocaine contributed to bankers' "culture of excitement and drive and more and more and more. It is a 'more' drug."
Nutt was famously fired from his position as the British government's senior drug advisor in 2009 after publishing a paper saying that there was "not much difference" between the harm caused by ecstasy and riding a horse. He also opposed the decision to upgrade cannabis from a class C to class B drug.
He was ordered to apologise by the then Home Secretary Jacqui Smith, who admonished him for trivialising the dangers of taking drugs. Nutt went on to say that alcohol and tobacco were more dangerous than many illegal drugs, including LSD, ecstasy and cannabis.
The professor spoke to The Sunday Times against the government's policy on hallucinogenic mushrooms, ecstasy and cannabis, which makes it difficult to study their beneficial qualities. He said the "insane" and "absurd" laws hindered harnessing psilocybin, the chemical found in the mushrooms, which could be used to treat depression.
"We have regulations which are 50 years old, have never been reviewed and they are holding us back, they're stopping us doing the science and I think it's a disgrace actually."