If the UK leaves the European Union (EU) on 29 March 2019 without an agreement, i.e. in case of a "hard" Brexit, the UK will not be longer be protected by EU trademarks and Community registered designs.
However, the British government intends that in the case of a hard or "no-deal" Brexit the protection for such trademarks and designs will continue:
Registered Union trademarks and Community designs remain protected in the UK as "comparable" trademarks and designs. The intellectual property rights retain their respective priority and registration data and are automatically entered in the register of the British Intellectual Property Office (UKIPO).