A look at the case of Ian Walters, who deliberately drove off the motorway at high speed to kill his wife Tracy. Tracy Walter's family are horrified when her murderer husband attends her funeral. Britain’s Darkest Taboos tells the stories of some of the most shocking and disturbing crimes within families and relationships. Every family’s worst nightmares are relived and re-told in unflinching detail by those left behind – by the families and friends, and by others whose lives have been touched - like the police officers and reporters involved in the cases. Each series looks into how the ones you trust the most can commit the most disturbing of crimes.