The term of the UK to decide on the details regarding Brexit has been postponed until 31 October 2019. During this period the United Kingdom will remain aligned with EU law, so that European trademark registrations will be valid in the UK. Keep in mind, the UK still holds the opportunity to decide on Brexit details at an earlier stage.
The draft EU-UK agreement provides a number of important subjects for the protection of EU trademarks in the UK, after Brexit:
The current European trademark registrations will automatically be converted into national UK trademark rights after Brexit. This will be different regarding EU trademark applications. Of course it is also possible to file a national trademark application in the UK.