Morphine turned out to be an excellent painkiller. During the First World War it was used on a huge scale to help wounded men sleep – or to let them die peacefully.

The soldier and physician John McCrae was probably referring to this in his well-known poem ‘In Flanders Fields’ (1915) when he wrote the words: “We shall not sleep, though poppies grow in Flanders fields”.

The poppies McCrae saw were probably not opium poppies,

however the association with the opium he was constantly administering is understandable.

Today, Britons wear a poppy every year on Remembrance Day to commemorate those who died in World War I.

Morphine is still used today to alleviate severe pain, for instance after an operation or a heart attack – or to relieve pain and suffering in people who are not going to get better.