Duty to Investigate
The obligation on the State to take indicators of trafficking or sexual exploitation seriously, and to carry out a genuine, effective investigation aimed at uncovering the truth and holding those responsible to account.
This information is not legal advice – it is meant to signpost information only. Please seek a professional opinion before taking action.
Legal definition
Pre-2004 (before the Sexual Offences Act 2003)
Although there was no trafficking-specific offence, authorities were under duties arising from general criminal law and Articles 3 and 8 of the European Convention on Human Rights to investigate credible allegations of serious sexual abuse, violence, and coercion.
2004–2015 (Sexual Offences Act 2003 era)
The creation of trafficking offences for sexual exploitation triggered ordinary criminal investigative duties. In addition, following ECAT (from 2009), the UK was under binding obligations to conduct effective investigations into trafficking and exploitation, regardless of when the conduct occurred.
Post-2015 (Modern Slavery Act 2015)
The duty to investigate is now firmly grounded in domestic law and reinforced by Article 4 of the European Convention on Human Rights, which requires investigations that are: prompt, independent, effective, and capable of leading to the identification and punishment of those responsible. These duties apply to historic as well as current exploitation.
What it looks like in real life
Authorities reopening or reviewing historic allegations of trafficking or sexual exploitation
Investigations that look beyond individual incidents to patterns, institutions, and enablers
Taking survivor accounts seriously even where reporting is delayed
Not dismissing allegations because the suspect is powerful, wealthy, or influential
Examining whether earlier failures to act contributed to ongoing harm
