The registration system is a way to connect drones to their owners, both to return drones which get lost and to ensure that operators are flying their drones responsibly. The registration is cheap, at just £9 ($12), but operators will need to take an online education course and test as part of the process. Once registration is complete, owners will be provided with a unique code that they must add to their drone to make it identifiable.
In addition to registering the drone itself, each person who controls a drone must obtain a flyer ID which requires taking a theory test. Children under 13 can still fly drones if they pass the test, but their parent or guardian must register for them. The operator of each drone must be over 18 and is responsible for ensuring that only people with a valid flyer ID pilot their drone.
Registration is mandatory for the operation of drones weighing more than 250g, and it must be completed by November 30th this year. Flying an unregistered drone after this time could result in a fine of up to £1000 ($1290).
In order to comply with these requirements and similar rules in the US, some drone manufacturers are deliberately ensuring their machines weigh in below the limit. DJI's Mavic Mini, for example, weighs exactly 249 grams.
To register a drone, you can head to the Civil Aviation Authority's website.