From 30 November 2019, Anyone responsible for a drone or unmanned aircraft (including model aircraft) weighing between 250g and 20kg needs to register as an operator. The cost for this is £9 renewable annually.
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.
Anyone flying a drone or unmanned aircraft (including model aircraft) weighing between 250g and 20kg must complete a 20 question multiple choice test every 3 years. This is the Flyer ID
If you have a PfCO, you don’t need to do the 20 question test. but you still need to pay £9 every year to register as an operator.
If you operate your drone you may be subject to a fine if you fail to produce, when requested by a police officer the relevant codes.