Animal welfare chiefs have blasted cruel dog owners who use Brentford's parks to groom their pets for dog fighting.

Dog walkers in St Paul's recreation ground have witnessed young men encouraging their Staffordshire Bull Terriers to attack trees, with some even hung from branches by their mouths to strengthen their jaws for the brutal and illegal 'sport'.

An eyewitness, who did not wish to be named, said: "There is a group of men with aggressive Staffies and when they are in the dog area, we all have to stay outside.

"They come in here all macho and try and encourage their dogs to be aggressive.

"They hang them by their mouths from the branches, it seems to me that they are training them for dog fighting."

Sue Cain, 50, of Grosvenor Road, who also walks her dog regularly in the St Paul's Road park, added: "I wont go in the dog area, one of them attacked my dog a while ago and I saw the owner using that aggressive tree technique. It's such a shame that somebody would do that to their pet."

In June the RSPCA revealed there had been a dramatic increase in the number of calls relating to dog fighting in England and Wales.

The charity received 358 calls in 2007 compared to 24 in 2004, with 132 specifically referring to youths or 'hoodies' fighting their dogs in the street or park.

Chief Officer Tim Wass said: "Our concern is that talk of dog fighting promotes images of 'dangerous' dogs, when in the vast majority of cases, it is the owner who is causing the problem, not the dog."

Vet Kara Murray, of Young Veterinary Practice, in Albany Parade, Brentford, said she has treated several animals who have been attacked by dogs in parks.

She added: "You see dogs around that are very scarred from fights but you won't see them in the vet as the owners tend to just leave them to heal themselves or do patch up jobs, as they are not the sort of people that care about the dog enough to get it proper treatment. It is very sad."