North Yorkshire Police recently used drugs detection dogs in the town centre of Harrogate.
The dogs are trained to detect all the commonly used drugs and patrolled outside many of the town centre late night venues.
Working around people in the street, the dog will indicate by stopping and then looking directly at a person it has picked up traces of drugs on. A search of the individual would then follow by the police.
This is all part of community policing to discourage people from using drugs.