The system of international drug control put into place during and after the First World War still endures today. As part of the Defence of the Realm Act, 1916, the possession of opium derived drugs by anyone not of a medical or veterinary profession was criminalised in the UK. International conventions on drug trafficking followed in the 1920s.Morphine and other opiates continue to be among the strongest pain killers available. Most of the legally extracted pure morphine is converted chemically to codeine, an effective painkiller. Less powerful than morphine, it is also less addictive. Today morphine is still used by the British Army. Morphine auto-injectors are issued to all British soldiers on active service, including in Afghanistan, allowing them to self-medicate in case of injury.