The new EU Prospectus Regulation ( No 2017/1129) is due to come fully into force throughout the European Union ( including the UK) on 21st July 2019 and replaces the EU Prospectus Directive (No 2003/71/EC).
It introduces a number of reforms designed to improve the quality of disclosure in prospectus documents as well as introducing a number of new concepts ( such as the "universal registration document", the "simplified prospectus" and the "EU growth prospectus") which will hopefully facilitate prospectus issues throughout the EU.
Prospectuses approved by national regulatory authorities in one EU member state should benefit from "passporting rights" throughout the EU BUT this will not apply to the UK following any "no deal" Brexit. It seems that prospectus issues approved by the UK authorities but not completed before "exit day" ( currently 11pm UK time on 31st October 2019) will have to be re-submitted for approval after exit day to the appropriate regulatory authorities of all EU member states where they are intended to be used after exit day.
The UK Government has published a draft statutory instrument - the draft Official Listing of Securities, Prospectus and Transparency ( Amendments etc) (EU Exit) Regulations 2019 - to customise the Prospectus Regulation to be appropriate in the UK for a "no deal" post-Brexit age but these Regulations will not solve the "passporting" issue.
Clearly, the World moves on even whilst the Brexit debate continues and the "Prospectus Regulation" example emphasises the detailed work that needs to be done on an on-going basis to try and ensure that commercial life throughout the 27+1 States can proceed as smoothly as possible.