Social and behavioural factors in Non-suspicious unexpected death in infancy; experience from metropolitan police project indigo investigation.

Background: Risk factors for Sudden Unexpected Death in Infancy (SUDI) are well described, and such cases are now investigated according to standard protocols. In London, Project Indigo of the Metropolitan Police provides a unique, detailed framework for such data collection. We investigate such data to provide a contemporary account of SUDI in a large city and further link data to publically available datasets to investigate interactions with social factors.