A teenager who stabbed an off-duty police officer after a row broke out at a McDonald’s branch has been sent to a young offender institute. Harvey Smalling, who was 19 at the time, had been drinking when he visited the fast-food chain and threatened to “knife” is victim. Off-duty officer Daniel Carter had been drinking at the Golden Lion in Rochester on July 17 last year with fellow officer Conor Keenan before the pair headed to McDonald’s in Commercial Road, Strood. It was there they saw Smalling, who is now 20, ordering his food on a nearby screen. Prosecutor Ryan Evans told the court: “They…