Almost 50,000 people have pledged to donate stem cells in order to save the life of three-year-old Scot Ava Stark.

The toddler from Lochgelly in Fife suffers from a rare blood condition which will prove fatal if a stem cell transplant is not performed.

In March, Ava had brought up a blood clot through her nose and was taken to Victoria Hospital in Kirkcaldy, where she started throwing up blood.

After going through an emergency blood transfusion, Ava was transferred to the Royal Hospital for Sick Children in Edinburgh, where doctors spent two weeks trying to discover what was making her so ill.

When the rare diagnosis of inherited bone marrow failure came through, her family was told she desperately needed a bone marrow transplant to survive.

Ava looked set to undergo the life-saving operation in August when a suitable donor was found but the family received the devastating news the anonymous donor was unable to go through with it.

Her mother Marie made a worldwide appeal following the blow and a second donor was found but medical reasons meant the person described by Ava as her "hero" had to pull out.

Potential donors have been registering to aid Ava's cause by filling out a form along with providing a saliva sample.

The match must be coherent with all of Ava's genetic markers for any operation to go ahead and should the stem cells be needed the procedure to extract them is similar to that of giving blood.

Since the deflating news of the second withdrawal the response has been emphatic, with almost 50,000 people putting themselves forward to help to save Ava's life.

The Anthony Nolan Trust has confirmed 16,000 people have pledged to donate since Tuesday morning, with an average in cases like Ava's usually reaching 100 pledges a day.

Ann O'Leary, head of regional register development at Anthony Nolan, said: "Through all that has happened, Marie and little Ava have been incredibly courageous and positive.

"A stem cell transplant is Ava's best chance of life but without a match that can't happen.

"We are urging people aged 16-30 to join the Anthony Nolan register. What many people don't realise is how easy it is to join - it simply involves filling in a form and providing a saliva sample."

She said: "If you're one of the privileged few who goes on to donate, 90% of the time this will take place via a straightforward outpatient procedure.

"The public's response to Ava's story has been over-whelming and shows just how incredible and selfless people can be when they rally together to save the life a stranger."

Information on how to find out if you would be a suitable donor can be found on the Anthony Nolan Trust's website.