The Law Enforcement Directive: journal article Conceptual Challenges of EU Directive 2016/680 Mark Leiser, Bart Custers European Data Protection Law Review, Volume 5 (2019), Issue 3, Page 367 - 378 The Law Enforcement Directive (EU Directive 2016/680) has been heralded for its role in building a high level of data protection in criminal law. Data processed for ‘law enforcement purposes’ by ‘competent authorities’ must comply with principles of necessity, proportionality and legality, while ensuring appropriate safeguards in place for data subjects. However, there is ambiguity as to how the LED should work in practice due to several conceptual issues that the LED raises. This paper discusses three conceptual issues: consent, the categorisation of witnesses, suspects and victims, and the categorisation of facts versus opinions. Keywords: Law Enforcement Directive, Fundamental Rights, Consent, Law Enforcement Data, Directive 2016/680