A client recently asked me if there were any guidelines on what personal data they could share with the police, as they were asked to give a statement after witnessing an event involving some young people.
The starting point is that the police, along with other law enforcement authorities, have legal powers to process personal data for law enforcement purposes; this is defined as “the prevention, investigation, detection or prosecution of criminal offences or the execution of criminal penalties including the safeguarding against and the prevention of threats to public security.”
However, the police and other authorities still have to work within the data protection regulations, and the ICO has a helpful page at https://ico.org.uk/for-organisations/data-sharing-information-hub/can-i-share-personal-data-with-a-law-enforcement-authority/