Bella's owner says she is at least 28 years old
A Derbyshire couple are trying to prove their pet Labrador cross is the oldest dog in the world.
Bella's owner David Richardson, 76, said he bought the mixed breed dog from the RSPCA 26 years ago when she was "at least three years old".
That would make Bella's age more than 200 in canine years.
But the RSPCA said it does not have any records for Bella and Guinness World Records said without the appropriate paperwork it could not be proved.
Mr Richardson said he thought Bella might be the oldest dog in England, but was shocked to realise that she might be the oldest in the world.
His partner Daisy Cooper said Bella was showing signs of her age, but still goes for a walk in the park.
She eats little as she has only two teeth left, but loves to suck on sweets.
Mr Richardson said when he went to the RSPCA to buy a dog he wasn't allowed to have an Alsatian because he was 50 years old.
"My choice was between Bella and another dog. She seemed friendlier so I chose Bella," he said.
Gareth Deaves, records manager from Guinness World Records, said "unless we can find some really clear evidence from the RSPCA" they would not be able to prove Bella's age.
According to Mr Deaves, the most recent record for the oldest dog was held by Butch, a 28-year-old from America who died in 2003. The oldest ever dog was Bluey, a sheepdog from Australia, who lived to 29.
David Richardson bought Bella from an RSPCA centre in 1982
BBC NEWS | England | Derbyshire | Derbyshire may have 'oldest' dog