Vets are warning of a “bull breed crisis” sweeping across London as increasing numbers of youths get dogs they cannot look after.

Animal charity Blue Cross deals with dozens of cases at its Bethnal Green mobile unit each week and says the number of badly-treated Staffordshire bull terriers being brought in is growing at an alarming rate.

Last year up to 90 per cent of Staffies needing a new home had to be turned away and most of them are likely to be put down.

Vetinary surgeon Nigel Griffiths said: “Young kids are getting these bull breeds because they are a fashion item or for some kind of protection.

“In the right pair of hands they make good pets but they need a lot of exercise, are very high maintenance and in the wrong pair of hands they are problematic. These are dogs with a big set of teeth on them and they can do damage.”

There has also been a worrying increase in the number of dogs with broken legs being brought into Blue Cross clinics because owners are not putting them on leads.

“This was very rare a few years ago but now we see several cases every week”, Mr Griffiths added.

A lot of the dogs entering the supply chain have been poorly bred and have various health problems but the biggest issue, according to the charity, is owners not getting them neutered.

Blue Cross chief executive Kim Hamilton said: “Neutering has proven medical and behavioural benefits and could help stop this vicious cycle of overbreeding and abandonment.”

Some of the shocking cases vets had dealt with were highlighted when Channel 4 show Undercover Boss ran an expose last week.

The Blue Cross has been offering free neutering for Staffies whose owners are on low incomes at its London clinics for the past five years.

See bluecross.org.uk/neuter.