They had never met but Hannah the German Shepherd turned out to be a mutt in a million when a fellow canine needed a helping paw.

For when ten-year-old labrador-retriever Herriot lost a massive amount of blood during a life-saving operation, Hannah bravely stepped up to make a vital donation.

Herriot was undergoing surgery to remove a huge 8lb tumour from his abdomen.

But although the operation carried out by vet Bronwyn Eastwood was successful, his owner Pat Balbuena feared her beloved pet was going to die.

The only way to save Herriot's life was an emergency blood transfusion.

But there was no blood available in the clinic until Tony Cowie, a vet and partner at the Coastway Veterinary Surgery in Brighton, stepped forward and offered his own dog Hannah as a donor.

Mrs Balbuena, 57, from Rottingdean, said: "I never thought dogs could donate blood to each other. I couldn't believe it."

Although it was his day off, Mr Cowie drove his pet to the Coastway clinic in Montague Place.

Blood was taken from Hannah by inserting a catheter into the jugular vein. It was pumped into a bag containing a liquid, which stops the blood from clotting, before being pumped into Herriot's veins.

Mrs Balbuena said: "I knew it didn't look good when they told me Herry needed a transfusion.

"Then they told me Mr Cowie was going to take his dog into the surgery to donate blood. It was amazing. He did it on his day off and with his own pet "It is major surgery and because of Herry's age I knew the risk of the anaesthetic and that there might be post-operative complications."

Once the transfusion was completed, Mrs Balbuena went to visit Herriot.

She said: "He looked so much better. He was so well I took him home the next day."

She nursed Herriot back to fitness over the next two weeks and he is now a picture of health.

She said: "It's given him a new lease of life. If I had known dogs could donate blood, I would have let Herriot do it. It's so vital."

Now Mrs Balbuena and Herriot are hoping to encourage other pets to donate blood at the Coastway surgery.

Animals must be young and healthy, medication-free, have no history of recent illness or fever, be of good temperament and happy with needles. Cats need to weigh at least 4kg and dogs ideally 20kg to 25kg.

A spokesman for the clinic said: "The donation is a procedure similar to human donations. Initially, a small sample of blood is taken to ensure the dog or cat is not anaemic. Then a line is usually inserted into the jugular vein to take the blood.

"Most pets don't even notice the needle but if the owner of the pet is at all concerned, the animal can be lightly sedated.

"Just like human blood, dog or cat blood cannot be kept for long periods before it is used so most transfusions need a donor before they can take place."

Dogs do not have to be matched for the first transfusion but would need to be for subsequent transfusions.

Anyone who can help should telephone the surgery on 01273 692257.