Trademarks are an important component in the system of undistorted competition in the UK. They play a key role for traders wishing to efficiently promote and sell their goods and services in the marketplace. Against this background, academics, practitioners and the United Kingdom Intellectual Property Office (UKIPO) have raised concerns with respect to the impact of overbroad trademarks and a clogged trademark register on the functioning of the UK trademark system. Past research by the UKIPO among UK-based trademark attorneys suggests that overbroad trademarks may engender uncertainty in terms of scope of protection and hence increased costs for third parties wishing to register new trademarks as additional steps are required for the purposes of trademark clearance. Similarly, it has been hypothesised that trademark clogging potentially blocks market entry for new products. Recognising the significance of the concerns associated with overbroad trademarks and non-use clogging, this chapter provides valuable insights into different aspects of UK trademark law aimed at curtailing such phenomena.