Despite the referendum, United Kingdom (UK) is still a member of European Union (EU). As a member of EU, UK still enjoys unified IP laws and protection throughout EU. If UK exits EU, UK would most likely lose the benefits of EU established IP protection.
1) Trademarks, Designs and Plant Variety
Community trademark (now known as EU trademark as of 23 March 2016), community design and community plant variety can be filed and enforced throughout EU member states. If UK leaves EU, the geographical scope of EU granted protection will be reduced to EU member states minus UK.
UK is a member of European Patent Convention (EPC) which is independent of EU. Norway, Switzerland and Turkey which are not members of EU are also members of EPC. UK will most likely remain as EPC member. However, UK may not be part of unitary patent implementation as EU membership is prerequisite for unitary patent.
3) English as official language of EU
EU free trade agreements with US and Asian countries are conducted in English. Currently, English is one of the official language for European patent. Will English be maintained as one of the official language of EU? English may have less influence in Europe due to widespread influence of French and German language. We hope that EU would not reduce the usage of English language as the rest of the world communicates in English.