The UK's oldest animal shelter says it had to put down hundreds of healthy dogs last year because they were too aggressive and unsuitable to rehome.
Battersea Dogs Home said about one in three of the dogs it took in last year were put to sleep - a total of 2,815 dogs, of which 1,931 were healthy.
It says more are being put down because their behaviour creates a safety risk.
The charity says one of the problems is people abandoning aggressive dogs when they become too hard to look after.
Scott Craddock from the charity told a BBC documentary that the number of aggressive stray dogs was shocking.
"We need to highlight exactly what is going on and we feel we've come to a point where enough is enough," he said.
Battersea Dogs Home doesn't turn away any stray or unwanted dogs and rehomes or returns about 5,000 every year.
Staffordshire bull terriers are among the most common breeds found in animal shelters.
At Battersea, the number of Staffies going to the shelter has rocketed 850% since 1996, but more often than not they haven't had even basic training to be able to get on with other dogs or people.