Many products require CE marking before they can be sold in the EEA (EU and Iceland, Lichtenstein and Norway).
CE marking proves that your product has been assessed and meets EU safety, health and environmental protection requirements. It is valid for products manufactured both inside and outside the EEA, that are then marketed inside the EEA. CE marking is valid only for products for which EU specifications have been introduced.
To affix the CE marking to your product, you must put together a technical dossier proving that your product fulfils all the EU-wide requirements. As the product's manufacturer, you bear sole responsibility for declaring conformity with all requirements. Once your product bears the CE marking, you might have to provide your distributors and/or importers with all the supporting documentation concerning CE marking.
The importance of demonstrating that your product conforms to the standards required within the EEA cannot be underestimated. Staying on top of changing requirements once the UK is outside the single market will be more of a challenge.