Although dog harnesses are used with sled dogs in mushing events, they also have everyday uses for public and private pet owners.

According to Mannix Security, a firm based in Leicestershire, its canine workers know it is time to go out and fight crime when they are put in their dog harnesses.

Spaniel Sam is one of the animals currently being used to sniff out mephedrone, a substance which was recently reclassified as an illegal Class B drug.

Operations director Alan Savill told the Harborough Mail he is training more canines to find this "extremely dangerous" substance at nightspots and schools.

"As soon as we put the harness on the dogs know they are working. They know they’ve got to find whatever the substance is," he remarked. "It’s a bit like play for them."

Last year, Scott Reynolds from Michigan’s Environmental Canine Services told the Detroit Free Press his canine companion Sable loves wearing his dog harness.

The clever animal sniffs out illegal sewer connections in the US state.