Is a European Union Trademark still valid in the United Kingdom after Brexit?

No, a European Union Trademark is not valid in the United Kingdom. After Brexit, which took effect on February 1, 2020, there was a transition period until December 31, 2020. During this time, trademarks registered in the EU were automatically recognized in the UK to ensure continued protection. However, trademarks not registered by the end of this period must be refiled in the UK. Applicants had until September 30, 2021, to refile their trademarks in the UK to retain the original EU application filing date.