The plan was outlined in a letter to local authorities and police forces from Home Office minister Vernon Coaker calling for cross-government efforts to stamp out knife crime. As part of the effort, Coaker said under-18s, working under the supervision of police and trading standards officers, will be sent to shops to attempt to buy knives illegally. Shop owners caught selling knives to under-18s face up to six months in prison and a fine of up to £5,000. Coaker said: "Knife...