The handler of the longest-serving fire investigation dog has said she is “immensely proud” that her newly retired pooch has been awarded a lifetime service medal.

Black Labrador Reqs, 12, became the 42nd recipient of the PDSA Order of Merit, which recognises animals that have shown “outstanding devotion to their owner or wider society”.

Reqs began his career in 2012 after he was seen to have traits which would make him suitable to become a fire investigation dog, and after specialist training, joined the Hertfordshire Fire and Rescue Service where he has attended over 500 fires and helped with high-profile investigations.

Attending a ceremony at Hertfordshire’s Joint Emergency Services Academy in Stevenage, Reqs’s handler – watch commander Nikki Harvey – shared her pride on seeing the black Labrador getting his medal.

“I’m immensely proud for Reqs to receive the PDSA Order of Merit award,” she told the PA news agency.

“It just sums up magnificently all the work that he’s done over the years and we’re just extremely proud of that.”

She said that when she met Reqs he already had “all the traits and attributes” needed to flourish in the Hertfordshire Fire and Rescue Service.

Ms Harvey said she has worked in the fire service in various roles for 30 years and is a “massive dog lover”, so was keen to take on the handler role when a vacancy appeared.

“For me, it was the dream job just to be able to work with a dog, as well as just having a dog,” she said.

“That interaction’s just amazing.”

She added that she quickly formed a bond with Reqs and now they are “the best of friends”.

She said that even though Reqs is retired, he still “loves” his tennis ball, as well as food, including a cup of tea.

Speaking about training a fire investigation dog, she said it is all “based on a reward”, in the form of the animal’s “favourite toy”.

“In Reqs’s case, that’s a tennis ball, so the initial search he is doing is for a tennis ball and then we build that up over a course of searches (so) he is identifying ignitable liquids,” she added.

“Then once he identifies the ignitable liquids, he then gets a tennis ball as a reward.

“We’re looking for dogs that have got a high search drive, they really want to play with their toy and interact with the toy, and not only just be given a toy to play with – which is obviously their ultimate reward for working – they want that drive to be able to search and hunt for it in effect.”

PDSA director-general Jan McLoughlin added: “We’re incredibly proud to be honouring Reqs with our PDSA Order of Merit today.

“His outstanding devotion to duty and service to society has been demonstrated time and time again throughout his long career, and his exceptional skills go above and beyond that of normal companionship, making him a very worthy recipient of the award.”