XL Bullies will likely be put down if they are not rescued in the next 24 hours, the Scottish SPCA has said. 

From Friday (February 23), it will become illegal for animal shelters to rehome the controversial dogs as new restrictions come into force. 

Any dogs meeting the criteria of an American XL Bully who have not been rehomed by that date will most likely be put to sleep rather than spend a lifetime in kennels.  

Read more: When are XL Bullies banned in Scotland? New rules explained

It comes after the Scottish SPCA put out an urgent appeal for four dogs which meet the physical standards of an XL Bully. 

A spokesperson for the Scottish SPCA said: " We have had a lot of applications for the dogs and we are remaining hopeful.

The Herald: Duchess is an XL Bully in the Scottish SPCA's careDuchess is an XL Bully in the Scottish SPCA's care (Image: SSPCA)

"As Scottish Government advice stands at present, it will become illegal for us to rehome these dogs if they have not found homes by 23 February.

"Keeping a dog in a kennel environment for the rest of their life is not good welfare, therefore this means we would need to consider putting these animals to sleep, if we cannot find homes for them before that date."

Meanwhile, Dogs Trust said it had been put in a "difficult position" by the new rules announced by the Scottish Government. 

Read more: Scottish SPCA urgently seeking homes for XL Bullies

The charity said: "In England and Wales, the law allowed rehoming organisations like Dogs Trust to apply for an exemption for dogs of type in our care, however it is not yet clear if this will also be the case in Scotland.

"While we wait for the Scottish Government to release more details, we are reviewing the individual circumstances and requirements of any dogs in our care in Scotland that we believe may be American XL Bully type to decide on the best outcome for them."

From February 23, the selling, gifting and exchanging of XL Bully dogs will be made illegal in Scotland. 

Also from that date, owners of the dogs must ensure they are muzzled and kept on a lead in public places at all times. 

Then, from July 31, it will be an offence to own an XL Bully in Scotland without an exemption certificate. Owners need to apply for one by that date. 

Read more: Scottish woman rescues more than 30 XL Bullies before ban

It comes after the dogs were linked to a number of attacks on humans, some fatal. 

However, a coalition including animal charities, the British Veterinary Association, and the UK Kennel Club has criticised the Scottish and UK Governments' approach, arguing that a ban will not stop these incidents from happening. 

Instead, the Dog Control Coalition is arguing for a "complete overhaul" of existing dog control legislation to tackle the "root causes" of dog attacks, which it says includes dealing with unscrupulous breeders and irresponsible owners whose dogs are dangerously out of control. 

More information and guidance on XL Bully dogs can be found on the Scottish Government and Scottish SPCA websites.