The Independent, 6 Feb 2014:
Your article on falling crime rates ranges across a variety of possible explanations without recognising that the evidence linking lead in petrol with violent crime is compelling (“The mysterious case of why crime is falling in Britain”, 24 January).
Crime rates worldwide rose after the Second World War in line with the use of lead in petrol, which peaked at 400,000 tonnes per annum in the early 1970s. Reduction in violent crime has been observed in all developed countries studied since then, and correlates very closely with the removal of lead from petrol with a lag period of approximately 20 years.
Thus in the US lead was removed between 1976 and 1980, and crime reductions occurred during the 1990s. Mayor Giuliani in New York was given credit for this, but in fact violent crime was falling before he took office and continued afterwards. In the UK and other EU countries lead was removed between 1985 and 1995 and we are now seeing the benefits in our own crime statistics two decades later.
Lead is a neurotoxin that exerts its maximum effects in utero and leads to disinhibited behaviour in adolescents and young adults. It explains most of the variance in violent crime since the Second World War.
Dr Robin Russell-Jones (Chair of the Campaign for Lead Free Air, 1984-89), Stoke Poges, Buckinghamshire