A £25,000 operation could transform the life of Newport man Simon Henson, left unable to perform even simple tasks by a rare muscular condition.

But after an agonising year-long wait, former fitness instructor and rugby player Mr Henson, 34, was told this month the Assembly will not fund the treatment.

The Health Commission Wales (HCW) say there is limited evidence the treatment works on Mr Henson's condition, a claim the neurosurgeon treating him says is "ridiculous".

Mr Henson suffers from focal tortocollis dystonia, a condition that causes muscle spasms, which cause the neck to twist to one side. It is not known what causes it.

The former Newport Centre lifeguard and Newport Saracens player was forced to give up a job with a tour firm in Austria in 2003 and moved back in with his mother, Val, and father, Terry, in Bishpool.

He now claims incapacity benefit and disability living allowance.

Mr Henson said: "I used to be so active but now I do nothing. I spend 24/7 in this house.

"I have to hold my head to keep it from shaking and I am in constant pain." In 2004 he saw an article in a national newspaper about a young girl with the condition treated by brain surgery by Professor Tipu Aziz, of Radcliffe Infirmary, in Oxford.

After a consultation Prof Aziz, the UK's only surgeon specialising in dystonia, offered Mr Henson the same treatment, Deep Brain Stimulation, which involves passing electrical stimulators through the brain to prevent 'rogue' messages reaching the muscles.

The operation would cost £25,000, plus a further £10,000 every 18 months to replace the batteries to the power pack attached to the abdomen.

Mr Henson has waited a year, but this month HCW told the Radcliffe they would not provide the cash.

An HCW spokeswoman said: "There is a weight of evidence to support the use of Deep Brain Stimulation (DBS) in Parkinson's disease, however, there are limited reviews of evidence on the use on DBS in other conditions including dystonia."

Prof Aziz said the situation is "frankly ridiculous". He added: "I have sent them evidence to support the success of this procedure."

Mr Henson's mother, Val, 53, said: "We are so angry. This is his only chance of having a life. Who are they to judge?"