It is currently uncertain when the UK will leave the EU and what the outcomes of Brexit will be.  However, successive UK Goverments have indicated that EU citizens visiting the UK for short periods will remain unchanged, at least in the short term.

If you have any concerns about visiting the UK after Brexit you can find out more about current UK government advice and information online,  This outlines what the parameters will be once UK leaves the EU, with or without an agreement with the EU.