The European Commission has sent an announcement stating that the effective date for Brexit with regard to IP rights will be 30 March 2019.
As of this date, the United Kingdom will become a “third state” and the registered and non-registered Community designs and EU trademarks will no longer be in effect in that country, but they will remain in effect of the other 27 Member States. The same will occur for pending applications.
This will likewise affect relations between the United Kingdom and the EU, as it will enforce the same requirements as those of the remaining non-member States.
See the announcement here.