CAA Drone Registration

As of November 30th 2019 all model aircraft flown in the UK MUST be registered with the CAA.

Anyone responsible for a drone or model aircraft must register as an operator. When you register, you'll get an operator ID with your certificate of registration. You must display your operator ID on your drones and model aircraft. You can use the same operator ID for all your drones and model aircraft.

https://www.caa.co.uk/Consumers/Unmanned-aircraft/Our-role/Drone-and-model-aircraft-registration/