“They came at dawn. Two police cars, full of officers, brake in front of Hope Cottage in Wilmslow. Sally is in the kitchen in her dressing gown. There is a knock at the front door …”

This is how John Batt, a solicitor who was part of Sally Clark's legal team, recorded the moment almost 10 years ago when her already shattered world collided with what was then the harsh reality of the investigation of sudden unexpected death in infancy (SUDI) in England and Wales.1 Much has happened since Mrs Clark's arrest in 1998 for the murder of her two infant sons, Christopher and Harry: her imprisonment in November 1999, the failure of her first appeal in October 2000, her successful appeal in January 2003, and, on 16 March this year, her own death.2 The consequences of Mrs Clark's case, devastating for her family, have also been far reaching for the medical and other professionals involved and for the child protection system as a whole in England and Wales.3 4 5 6

A positive legacy is, however, emerging from the tragedy. From April next year all sudden unexpected infant deaths in England and Wales will be investigated in accordance with a new multiagency protocol, introduced as part of the reforms of the 2004 Children Act and as a direct result of the Clark case. The overriding principle, set out in the statutory guidance for the operation of the protocol, is now this: “Each unexpected death of a child is a tragedy for his …