Dark patterns describes user interface and design techniques intentionally structured to manipulate or unduly influence user behaviour, for example to obtain consent, drive purchasing decisions, or discourage exercising data protection or consumer rights. The term is primarily descriptive rather than a defined legal concept in UK or Irish legislation, but is increasingly used by regulators, courts and practitioners in the context of consumer protection, e‑commerce and data protection law. In practice, dark patterns may include pre-ticked boxes, confusing consent flows, misleading button hierarchies, obstruction of cancellation processes, or exploitative “choice architecture” that nudges users away from privacy-friendly or consumer-protective options. In the UK (including England and Wales, Scotland and Northern Ireland) and Ireland, such practices are typically assessed under existing rules on unfair commercial practices, misleading or aggressive practices, transparency, and valid consent (notably under UK GDPR and the EU GDPR in Ireland). Regulators such as the CMA, ICO and the Competition and Consumer Protection Commission have identified dark patterns as a compliance risk, and their presence may evidence unfairness, invalid consent or lack of transparency, exposing traders and controllers to enforcement action, fines and contractual or statutory claims.