The grandfather-of-four, 52, has battled incurable multiple myeloma for two years, and a transplant is his only hope.

So the former naval diver – known as Spike – was delighted when more than 70 strangers turned up to a special session for new recruits at David Lloyd Leisure in Port Solent, Portsmouth, last night.

Sadly, some people were turned away because of strict rules on who can donate, but 48 people signed up and now they could be able to help Mr Spears – or thousands of other people waiting for a vital operation – have life-saving surgery.

Despite being drained, Mr Spears, of Neville Avenue, Portchester, still made the effort personally to thank as many people as possible.

He said: 'Hopefully there will be a match in there somewhere. It would be like winning the lottery – except I don't need the money, I need someone to save my life.

'I'm really grateful to everyone who has made the effort. I've got a lot left to do and I can't cram it all into such a short space of time.'

Mr Spears endured a procedure to harvest stem cells from his body and replant them last year, which extended his life.

But this procedure is estimated to be effective for only about 18 months, so Mr Spears and his family are desperate for a donor for a transplant which could give him years more to enjoy seeing his family growing up.

Daughter Hazel Fenn, 30, who organised the session, said: 'It's overwhelming how generous people are. They don't know dad personally but have still come here and signed up. We're really grateful. Without them we would have even less chance of finding a match.

'At least we've been able to do this while dad is well enough to appreciate what's going on around him.

'Things will get worse and we know it's only a matter of time.

'If it doesn't help him at least it might help someone else.'

Anthony Nolan Trust donor recruitment manager for the south east Debbie Jepps said: 'The family were overwhelmed by the response from these people who don't even know them.

'Any one of them could save a life, whether it be Spike's or someone else's.'

To see how to sign up, click Next Page.