At present, the CE sign must be attached to many products (including medical equipment, toys, machinery, and electrical equipment) which are placed on the market in the EU to show compliance with the relevant UE law on product safety. In many cases, the product can be declared according to the manufacturer, which can then affix the CE sign.
Mostly, but not all, the product in which the current CE sign must be applied will fall within the scope of the new British product marking regime following Brexit. The new UK sign is a 'UKCA' (Ensess Reachity assessed). The rules around using the new UKCA mark will reflect those who currently apply to the application of CE. You can consider the best ukca mark to be used for goods being placed on the market in Great Britain (England, Wales, and Scotland).
In most cases, it will still be possible to use CE marks for products placed on the UK market after March 29, 2019. However, this is intended for a limited period of time. The British government has said it will consult with the industry and provide notice before ending the limited period of this time.
So for at least time, and with one exception described below, the product marked CE can continue to be placed on the market in the UK after Brexit has no further assessment or marking. The exception is where the product in question requires a third party's assessment of conformity, and what has been done by the English suit assessment agency.
In such circumstances, it is necessary to apply a new UKCA sign from March 29, 2019. It will not happen but if the certificate of suitability has been transferred to the UE-recognized body before it (in this case the CE sign can still be applied, making the product acceptable for the market English).
As far as possible, the British government has tried to minimize interference caused by Brexit 'no agreement' by continuing to allow products marked CE to be placed on the market in the UK, although for a limited period of unspecified time.