Beloved British author TERRY PRATCHETT has refused to rule out euthanasia as he battles Alzheimer's disease.

The writer, 59, - who announced he was suffering from a rare form of the disease in December (07) - says medically-assisted death is an option for people battling the degenerative disease.

He says, "My view is that when there is clearly no 'me' left, whatever else might be left, then painlessly disposing of the remnants would be a sensible idea."

Meanwhile, Pratchett - who this week (ends14Mar08) donated $1 million (GBP500,000) to the Alzheimer's Research Trust - is determined to continue writing.

He says, "My plan is to do two more books. I believe that should be possible and hope I will do more.

"But the moment it becomes physically difficult and too problematic then, well..."