A police officer stabbed as he tried to defend his dog from an armed suspect has described the "harrowing" moment he was compelled to spring to the wounded animal's defence.
Stevenage Pc David Wardell suffered hand injuries as he sought to apprehend a 16-year-old, who attacked police dog Finn as he tried to make his escape.
The dog underwent extensive surgery before retiring to action. The teenage defendant, who cannot be named because of his age, was convicted of attacking the police officer, his dog, and possessing weapons.
Speaking after the case, at Stevenage Youth Court, Mr Wardell said reliving the experience in court had been difficult.
"It was very emotional, something that will be forever on my mind - it wasn't difficult to relive those moments.
"It's such a huge relief to have actually got into that room and given evidence because I wasn't sure we'd actually get to that point.
"It's not a difficult incident for me to relay, it's probably the most harrowing that's ever happened to me.
"And to have my faithful friend and partner go through that - if you asked me to relive it in ten years' time I could do it exactly the same."
Mr Wardell gave his backing to the introduction of Finn's Law, increasing sentences for criminals who attack working animals such as police dogs and horses.
The campaign had been supported by more than 100,000 people before the moves were halted by the announcement of the General Election.
He said: "There is a campaign running and it will be down to the government of the day whether they make changes to the laws that currently exist."
The teenage boy, from south London, was convicted following a day-long trial.
The court heard the 16-year-old plunged the 12-inch (30cm) hunting knife into Finn after being pursued by Mr Wardell.
The boy said he was acting in self-defence after fearing for his safety and being "bitten up" by the animal.
Mr Wardell broke down in tears as he described the moment he feared for his life, and that of his dog, as the suspect brandished "the largest knife" he had ever seen.
The suspect said he only ran from police, through Stevenage in the early hours of October 8, after becoming worried about being caught with the blade.
But district judge Jo Matson found the boy guilty of actual bodily harm, as well as criminal damage to the dog, and warned he could face jail when he was sentenced next month.
The judge said the defendant's evidence was "not credible or truthful".
She added: "His evidence does not add up. I do not accept that he found it necessary to take the actions he did to defend himself.
"He put himself in a position where it was necessary for Finn the police dog to stop him from running away with a knife in his hand.
"Stabbing a dog you know to be a police dog and lunging a knife at a police officer were not necessary or proportionate and I do not find he (the defendant) believed them to be at the time.
"Pc Wardell gave very emotional evidence today and was clearly very distressed by what happened that day, and still is."
Addressing the youth, who had his mother by his side at court, the district judge said: "All sentencing options remain open, including custody."
Finn required a four-hour operation, including having two sections of his lung removed, after being stabbed in the body and head.
The court heard the knife narrowly missed the dog's heart. He returned to the force after making a recovery and has subsequently retired from service, Hertfordshire Police said.
Mr Wardell suffered a cut to the hand after running to the aid of his dog.
Recalling the incident, Mr Wardell said: "It was the largest knife I've ever seen. "Finn didn't let go at all of the suspect. I was in fear of my life, and in fear of Finn dying in front of me.
"Finn is one of the highest trained dogs in the police force, I wished neither Finn nor myself were in that garden, but we were."
The youth will be sentenced in Bromley, south London, next month.