THE dog left at a railway station with a suitcase of his belongings is to undergo eye surgery today after thousands of pounds, dollars, euros and yen were raised for the operation.

Andy Murray and Irvine Welsh were among the thousands who joined the online surge of support and offers of adoption for abandoned Kai, making him the most popular dog in the Scottish SPCA's history as his story went viral and inspired giving from wellwishers across the world.

An appeal was launched by the charity and more than £2,500 was raised in less than 24 hours for Kai's surgery, which will take place in the veterinary clinic at the Scottish SPCA centre at Cardonald, Glasgow today, and his care and that of other animals.

The charity expects to rehome him in Scotland in around three or four weeks after he has had the operation to his eyelids, which are curled under meaning his eyelashes touch his eyeballs.

The Shar-pei crossbreed hit the headlines from the US to Japan and the charity has had calls from people in California and Tennessee offering to adopt him.

Tennis star Murray retweeted Kai's plight and writer Welsh said the act of abandoning him was "despicable".

Kai, who is aged between two and three, was discovered at Ayr railway station in South Ayrshire a week ago by a member of the public who contacted the Scottish SPCA.

He had been left with a case containing a pillow, toys, food and his bowl in a manner reminiscent of the fictional character Paddington Bear.

Alan Grant, the Scottish SPCA's senior animal care assistant who is looking after Kai at the charity's centre in Glasgow, said yesterday: "In less than 24 hours we have raised over £2,500 for Kai, which is simply amazing.

"We have been overwhelmed with the response from people around the world and would like to thank everyone who has made a contribution, offered Kai a new home or wished him well.

"The donation page was originally started so people could help pay for the operation Kai needs on his eyes and any additional funds will be used to help care for the many sick, injured and abandoned animals at our rescue centres across the country.

"We've never had a response quite like this before and it is wonderful to know there are so many kind hearted animal lovers out there."