Introduction: Linking longitudinal cohort resources with police-recorded records of criminal activity has the potential to inform public health style approaches to policing, and may reduce potential sources of bias from self-reported criminal data collected by cohort studies. A pilot linkage of police records to the Avon Longitudinal Study of Parents and Children (ALSPAC) allows us to consider the acceptability of this linkage, its utility as a data resource, differences in self-reported crime according to consent status for data linkage, and the appropriate governance mechanism to support such a linkage. Methods: We carried out a pilot study linking data from the ALSPAC birth cohort to Ministry of Justice (MoJ) records on criminal cautions and convictions. This pilot was conducted on a fully anonymous basis, meaning we cannot link the identified records to any participant or the wider information within the dataset. Using ALSPAC data, we used summary statistics to investigate differences in socio-economic background and self-reported criminal activity by consent status for crime linkage. We used MoJ records to identify the geographic and temporal concentration of criminality in the ALSPAC cohort. Results: We found that the linkage appears acceptable to participants (4% of the sample opted out), levels of criminal caution and conviction are high enough to support research, and that the majority of crimes occurred in Avon & Somerset (the policing area local to ALSPAC). Those who did not respond to consent requests had higher levels of self-reported criminal behaviour compared to participants who provided explicit consent. Conclusions: These findings suggest that data linkage in ALSPAC provides opportunities to study criminal behaviour and that linked individual-level records could provide robust research in the area. Our findings also suggest the potential for bias when only including participants who have explicitly consented to data linkage, highlighting the limitations of opt-in consent strategies.