recently retired President Obama.

Further south, in Mexico, the legalisation might end the bloody war between gangs and police and inject money into the official economy. In the Caribbean, home to some of the worst per capita violence in the world, the closing down of illicit drug routes might produce profound changes in civic society, with gangs no longer killing each other in drug territory battles.

But what of the scale of the health and addiction problems at home and abroad? There would be a rash of Daily Mail stories about dead teenagers, but around the world governments would adjust to the fact that they will - perhaps only briefly - have to invest in health education and rehabilitation programmes with the same enthusiasm with which they once built jails; after all, health ministers now point to the decline in cigarette use in countries where education programmes have been tried.

In the UK in 2008, there were four million problem drinkers and alcohol was implicated

in 40,000 deaths each year; there were ten million smokers and tobacco was implicated in 120,000 deaths; there were a million legalised tranquiliser users and 340,000 problematic heroin and crack cocaine users. In 2018, with legalisation, there would be an initial increase in drug use but the billions released into the public purse by legalisation, through taxes on drugs and the emptying of jails and courts, could swiftly be put into use.

Sadly, there will always be casualties; whether drugs are legal or illegal, you cannot make addictive personalities illegal. But there is no need for the economies and political infrastructures of poor countries to be perverted as they are now by the savage effects of keeping drugs illegal.