LONDON: British author Terry Pratchett, who has Alzheimer's, Tuesday defended making a film showing a man dying at an assisted suicide clinic in Switzerland. Assisted suicide is illegal in Britain and anti-euthanasia campaigners complained that the program “Choosing to Die”, broadcast by the BBC Monday, could prompt copycat suicides. Pratchett told the BBC he made the film “because I was appalled at the current situation. I know that assisted dying is practised in at least three places in Europe and also in the United States.” The film showed Pratchett watching as Peter Smedley, 71, a British man with motor neurone disease, travels to the Dignitas clinic near Zurich where he takes a fatal dose of barbiturates. “Peter wanted to show the world what was happening and why he was doing it,” said Pratchett, whose books about Discworld, a flat universe balanced on the back of four elephants which themselves stand on a giant turtle, have sold 55 million copies worldwide. The writer was diagnosed with early onset Alzheimer's in 2008 and now campaigns on the issue. Dignitas has gained notoriety over the past decade by offering more than 1,000 foreigners the opportunity to take advantage of relatively permissive Swiss laws.