From the outset, one big question has haunted detectives looking into the death of young Welshman Gareth Williams. How could his body have ended up locked inside a relatively small bag in the bath at his apartment in Central London?! In this episode Dr Sian Williams hears from two people who have attempted to lock themselves inside a similar size holdall but with altogether different outcomes

Death of a Codebreaker is presented by Dr Sian Williams with contributions from Lewis Allsop, Wayne Wright and Dyfan Rees.