In 1961 the Suicide Act made suicide legal in England and Wales but it remained a criminal offence to assist or encourage someone else to commit suicide. In 2010, following a successful legal battle by multiple sclerosis sufferer Debbie Purdy, new guidelines were published on assisted suicide to clarify when people were likely to face prosecution. Gary Slapper, Professor of Law at The Open University discusses the case and its implications on assisted suicide and mercy killing with Frances Gibb, legal editor of The Times.