They were once top dogs in the police, springer spaniels who sniffed out drugs and explosives.
Now Nelly, Midge and Milly are using their incredible sense of smell to find gas leaks, leading engineers to minute cracks in underground pipes.
Their owner, retired police dog instructor Steve Foster, 58, trained the dogs to detect gas escapes.
He said: “Some escapes can be really, really difficult to find.
“The dogs’ noses are thought to be anywhere between 10,000 and 100,000 times better than a human’s nose.
“So, they can find minute amounts of gas. That can be all you need, the golden nugget the engineers need to start with.”
Steve, from South Shields, Tyne and Wear, was contacted by gas company Cadent, which manages all of the 21,000 miles of gas mains which run across North West England.
Rachel Endfield from the firm said: “We are determined to find innovative ways to tackle this and prevent our customers from losing supply.
“I’d heard about the gas detection dogs that Steve has trained for exactly this job.”
“We’ve had them in the North West network for two days now, the first time we’ve used them.
“We have seen some really fantastic results already.”
David Leah, repair team leader for Cadent Gas, said: “The dogs are going to be a great asset for us.
“When we dug down to where the dogs detected something, it was spot on, or, a foot away at most.
“It was unbelievable.”
