A runt of the litter who was left to wander as a stray could now hold the title of Britain's oldest dog - after turning 22 years old. Jack Russell Daisy was rescued by owner Mark Barsby-Finch in 1993, when she was a two-year-old pup at a rehoming centre. But twenty years on, the pampered pooch is still going strong. Experts calculate that the terrier is the equivalent of turning 100 in human years - after scrapping the traditional claim that one dog year equals seven human years, as different breeds of dog age differently. And Mark, from Teweksbury, Gloucs, puts Daisy's longevity down to her long walks in the countryside - and refusing to eat dog food. Mark said: "Daisy has never had a tin of dog food in her life, she eats exactly what we eat. "Her favourite meal is roast chicken and mashed potatoes, but she'll happily eat anything. "She's partial to a takeaway Chinese, and she loves a homemade chilli too, as long as it's not too spicy. "I wouldn't dream of giving her scraps - I cook an extra portion of food just for her, and she eats before the rest of the family. "She's definitely a very pampered pooch, but she deserves it. She's given us a lot of pleasure over the years." Mark adopted Daisy from Cheltenham Animal Shelter for his niece, Claire, back in 1993, after she had begged her family for a dog. Animal shelter workers didn't have an exact date of birth for Daisy - but believed her to be at least 24 months old when Mark adopted her. Although the oldest dog ever known to have lived in the UK reached the age of 26, it is believed that Daisy is the current oldest dog in the country. When Mark's sister's family moved into a home that needed major renovations, Daisy moved back in with Mark, after she gained a reputation as an escape artist. But when works on the house were completed, two years on, in 1999, Daisy decided she didn't want to move back, and made it clear she'd rather stay put in Mark's home, where she has lived ever since. Mark added: "When we rescued Daisy, they told us she was the runt of the litter and wouldn't have been expected to survive long. "She was left to wander farmland as a stray before someone found her and took her to the shelter. "When we first adopted her, we had access to 40 acres of farmland, and Daisy used to be off out into the fields first thing in the morning, and she'd suddenly reappear just in time for her tea. "She has always hated going for walks on the lead, but give her a field to run around and she's off. "Her favourite treat is to have a couple of ice cubes to play with. I used to have an ice machine, which was quite noisy, and she figured out how to knock it so the ice fell to the floor. "I give her one or two cubes as a treat now and then, and she loves them. "She spends most of the time sleeping now, but apart from being missing a few teeth and  being a bit hard of hearing, she's in really good health. "We don't know the date of her real birthday, but we have always celebrated it on the day we adopted her, February 21. "We had a little party for her, and let her have a bit of cake - but the humans probably enjoyed it more than Daisy. "Hopefully we'll be celebrating many more birthdays to come."