Pet owners were warned yesterday of a growing trend in dog thefts, with some owners threatened with weapons and ordered to part with their animals.

In some cases, thieves are breaking into homes and confronting dog owners before making off with their pets, according to the group Dog Theft Action.

The organisation, launched at last year's Crufts, is calling for a national database for lost, stolen and found dogs in a bid to tackle the growing problem of thefts.

It also believes if vets, dog wardens and rescue centres routinely scanned dogs as they came in, many may be reunited with their owners.

Margaret Nawrockyi, who founded the group, attended Crufts yesterday at the National Exhibition Centre, to warn fellow dog owners about the trend.

She had her Cavalier King Charles spaniel stolen from her garden in Lincolnshire three years ago and has heard nothing since.

"We are here to raise awareness and encourage responsible dog owners that dogs are being stolen and thefts are significantly rising in number. I know it is on the rise by the amount of telephone calls I am receiving.

"Half a million dogs a year are microchipped so we need to encourage vets to scan any new dogs that they see and urge rescue c entres to scan the animals.

"There are no national statistics on dog thefts because the offences are lumped in with burglaries and vehicle thefts but we are aware of a rise.

"People can no longer tie their dogs up outside shops or leave them in cars. We had one case where a woman had left her dog in a van for five minutes and came back to find it had been stolen."

Mrs Nawrockyi said there were three types of dog thieves operating across the country.

They are the professional thieves, who look for certain types of dog; opportunists, who go for any dog in the hope they can sell it on quickly at a pub or market; and spiteful thieves, who could be disgruntled neighbours or ex-partners wanting to cause upset to the targeted dog owner.

The most common dog to be stolen at the moment is a springer spaniel, although Staffordshire bull terriers were also a target, she said.

Mrs Nawrockyi was joined at Crufts by her colleague Nikki Powditch, who believes her dog was stolen before it was found dead on a road last year.

Ms Powditch only discovered her rottweiler Jester had died when she found a few remains on the roadside and had them DNA tested.

She is calling on local authorities, dog wardens and Network Rail to scan for microchips before incinerating any dog they find dead.

"We were walking in the woods two miles away from the road when Jester went missing.

"Somebody told me they had seen a dog's body on the road but by the time I got there it had been taken away, incinerated and turned into bonemeal. If they had scanned the dog they would have found out who owned it and could have told me."

Ms Powditch has since persuaded the Highways Agency to scan any dogs found on the roads.