After a two-year legal battle and 200,000-strong petition to keep the dog alive, Lennox was put down by Belfast City Council following a court order.

Belfast City Council confirmed that Lennox, who was categorised as an illegal pit bull terrier type, was put to sleep on Wednesday morning.

A huge campaign to save the seven-year old dog reached as far as New York and had the support Northern Ireland’s First Minister Peter Robinson. Celebrity dog trainer Victoria Stilwell, presenter of It’s Me or the Dog had also offered to re-house the dog in the United States.

But the council accepted the ruling by Northern Ireland’s Court of Appeal and the dog was put down.

In a statement, the council said that an exemption could not be applied in this case: “The council’s expert described the dog as one of the most unpredictable and dangerous dogs he had come across.”

Kellie Wetton from the Save Lennox campaign said she was “devastated”.

“I just don’t understand what they say about him being deemed dangerous when he’s never hurt anyone – even in two years being in kennels. And there were options for them to re-home him. He could have been exempted, but they chose not to do that,” she told Channel 4 News.

The campaign to save Lennox has garnered 200,000-strong petition and a huge amount of support, with the hashtags #saveLennox and #saveNIone taking hold of Twitter.

However some campaigners turned on Belfast City Council, and in a statement, the council said that staff had been subjected to intimidation and abuse, including death threats from campaigners, which had been reported to police. The Facebook page for Belfast’s offical tourism site, Go to Belfast, has been temporarily shut down after being inundated with comments about the campaign and some users have commented that will boycott Belfast as a result of the decision.

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Two-year legal battle

Lennox was taken from his home in 2010 and a two-year legal battle ensued as his owner, Caroline Barnes, sought to overturn the decision. Last month, Northern Ireland’s most senior judges rejected an appeal to overturn the decision of two lower courts which deemed him “unpredictable”. Midnight on Tuesday was the the final day of the 28-day reprieve.

The dog was categorised as an illegal section 1 pit bull-type after fitting a set of specific measurements. His family and campaigners argued that he was part Labrador, part American bull dog.

Ms Barnes insisted he was not dangerous, and that he formed a close bond with her daughter, now 14. Following the Court of Appeal verdict in June, the family had accepted the dog could not come home, but hoped the council would accept the re-housing option, a Save Lennox campaign spokeswoman told Channel 4 News.

In a statement released on Facebook late on Tuesday night, the Barnes family said: “We are sorry to say at the present time Belfast City Council seem to be intent on killing our boy.

“Despite previous assurances otherwise, we have been denied the opportunity to say goodbye. We have also been told that we cannot collect his body and bring Len home. We have been informed however that we will receive ‘some’ ashes in the mail.”

The United Kingdom has a breed-specific ban on American Staffordshire terriers, more commonly known as pit bulls, which was extended to Northern Ireland last year. Under the Dangerous Dogs Act 1997, pit bull-terrier type dogs can be put down if they are deemed a danger to the public.

Current legislation ‘failing the nation’

Legislation that bans dogs based solely on their breed has been controversial in the UK and a spokeswoman from the Battersea Dogs and Cats Home told Channel 4 News that the current laws are “failing the nation”.

“Whilst it is unacceptable to have dogs in the community that are a danger to society, it is equally unacceptable for the current legislation to condemn dogs by breed, regardless of their nature,” said Dee McIntosh from the Battersea shelter.

“Every dog should be judged by what it has actually done, rather than what it looks like and it’s time we held irresponsible owners to account.”

The home took in 168 dogs that were later identified by the police as illegal banned breeds and were therefore put to sleep under the law. But dog handlers at the home said that 90 per cent of them had good temperaments and posed no threat to the public.