"I put my finger in," Mr Spievak says, pointing towards the propeller of a model airplane, "and that's when I sliced my finger off."

Today though, you wouldn't know it. Mr Spievak, who is 69 years old, shows off his finger, and it's all there, tissue, nerves, nail, skin, even his finger print.

'Pixie dust'

How? Well that's the truly remarkable part. It wasn't a transplant. Mr Spievak re-grew his finger tip. He used a powder - or pixie dust as he sometimes refers to it while telling his story.

Mr Speivak's brother Alan - who was working in the field of regenerative medicine - sent him the powder.

The process he has been pioneering over the last few years involves scraping the cells from the lining of a pig's bladder.

It can be turned into sheets, or a powder.