Jack Sprat the greyhound looked promising in training, reaching 40mph, but when he started coming last in competitive races his owners became confused.

Little did they know poor Jack did well to keep up at all as the hound is almost completely blind.

Now Jack is being cared for at the Dogs Trust in Snetterton and is looking for a new home away from the racetrack.

With no sight in his left eye and very little in his right, the three-year-old is not letting his disability get in the way of having fun.

After working out where the boundaries of the paddock are he loves to run around the rehoming centre, near Thetford, and stretch his long legs. And in the time he's been there some of Jack's little traits have already become noticeable.

One of the most obvious is his preference for walking on the left to take advantage of the remaining sight in his right eye and kindly saving his carer from bumping into him.

Supporter Relations Officer at Dogs Trust Snetterton, Kate Brewster, said: 'Jack is a handsome lad and has a very sweet nature, things that catch him unaware like unexpected movements or big cuddles can make him nervous, but with a little time and patience this will become a thing of the past.

'Jack is a typical greyhound and, once he gets used to home comforts, would love nothing more than to settle down on a sofa or comfy chair for a snooze next to his new owner. With a love of food and hugs, both will help this loveable fella settle in and become a fantastic companion.'

Jack, who was born in Ireland, was entered into dog races in Wimbledon, London, last year after he hit speeds of 40mph in training.

Despite his disability, Jack can still run 100 metres in just 6.39 seconds - considerably faster than athlete Usain Bolt who broke records with his 9.69 time.

But Jack, competing under the name Centurys Gunner, came sixth in both of his races at the Wimbledon Greyhound Stadium.

His baffled owner, believing he just wasn't fast enough, retired him and handed him over to the Dogs' Trust in Snetterton in July this year.

Vets at the animal charity examined Jack and realised a rare condition had left him completely blind in his left eye and with only 20pc vision in his right.

They diagnosed him with Chorioretinitis, a swelling and irritation of the middle layer of the eye, which is irreparable.

Ms Brewster said Jack would have been 'terrified' while racing with no vision in his left eye, used by dogs to follow the rabbit.

She added: 'We don't think Jack's racing owner realised the severity of his blindness and it would have been terrifying for him to race because of the noise.

'He must have followed the other dogs or maybe used his sense of smell to get around the track. He clearly had no way of seeing the rabbit.

'Jack can still run very fast and now he knows where the fences are on the paddocks at the centre he gets up to impressive speeds. Like any dog he needs regular exercise but it is a myth that greyhounds need long walks because they are born sprinters.

'We take on quite a few greyhounds but they often get overlooked because smaller dogs are in fashion.

'It's a shame because they are very gentle dogs and like a lot of affection. Jack is lucky as he is very handsome and has beautiful markings. He would make a lovely pet.'

The Dog's Trust would like to rehome Jack but recommend he lives in household with children no younger than 11, and without small pets he could chase.

If you would like to offer Jack, or any others from the Dogs Trust, a home either visit the centre or the website www.dogstrust.org.uk.