Plot: Following the BBC Two documentary at 9pm tonight entitled Terry Pratchett: Choosing To Die, Newsnight have an interview with Mr Pratchett and Jeremy Paxman chairs a debate about the controversial issues surrounding assisted dying. Our guests in the studio will be David Aaronovitch, Dr Erika Preisig, Debbie Purdy, Dinah Rose QC, Liz Carr and The Rt Revd Michael Langrish Bishop of Exeter