Campaigners have welcomed the move to outlaw the breed they argue is “a clear and present threat to public health”, but concerns have been raised it may not be practical and lead to other kinds of dogs being prohibited.
American XL bully dogs are a danger to communities and will be banned, Rishi Sunak has vowed, after a man was mauled to death.
Announcing the move, the prime minister said he “shared the nation’s horror” at such attacks and they could not be allowed to continue.
Mr Sunak was responding to the latest incident in which a man died after being savaged by two dogs outside a property in Stonnall, Staffordshire, on Thursday afternoon.

A ban on American XL bully dogs was already being looked at after shocking footage emerged of an attack in Birmingham last weekend that left an 11-year-old girl with serious injuries.
South Yorkshire Police reported four separate dog attacks on children in two days, including one where a 15-year-old was taken to hospital after being savaged by an XL bully in Sheffield.
Police in London are also hunting the owner of a grey pitbull-type dog that attacked a four-year-old boy on Monday.
But the Dog Control Coalition, which encompasses animal charities including the RSPCA, Dogs Trust and the Kennel Club, said banning XL bully dogs will not stop attacks.
Any ban should be based on “robust evidence”, a spokeswoman for the coalition said – adding it was “deeply concerned” by the “lack of data behind this decision and its potential to prevent dog bites”.
She added: “The biggest priority for everyone involved is to protect the public – but banning the breed will sadly not stop these types of incidents recurring.
“For 32 years, the Dangerous Dogs Act has focused on banning types of dog and yet has coincided with an increase in dog bites, and the recent deaths show this approach isn’t working.”
The coalition is urging ministers to tackle the “root cause” by dealing with “unscrupulous breeders putting profit before welfare”, and “irresponsible owners”.
Sunak: ‘This cannot go on’
Earlier, in a video statement posted to X, formerly known as Twitter, the prime minister said: “The American XL bully dog is a danger to our communities, particularly our children.
“I share the nation’s horror at the recent videos we’ve all seen. Yesterday we saw another suspected XL bully dog attack, which has tragically led to a fatality.
“It is clear this is not about a handful of badly trained dogs, it’s a pattern of behaviour and it cannot go on.
“While owners already have a responsibility to keep their dogs under control, I want to reassure people that we are urgently working on ways to stop these attacks and protect the public.
“Today I have tasked ministers to bring together police and experts, to firstly define the breed of dog behind these attacks, with the view to then outlawing it.
“It is not currently a breed defined in law, so this vital first step must happen fast.
“We will then ban the breed under the Dangerous Dogs Act and new laws will be in place by the end of the year.
“These dogs are dangerous, I want to reassure the public that we will take all necessary steps to keep people safe.”