For anyone either responsible for, or flying, drones on unnanned remote aircraft, like modrl planes and helicopters, new rules appear to have come into force today ... Nov 5th, 2019.
I've only read them quickly, but "responsible for" seems to include owning, whether you personally fly them or not.
Up to two ID's may be required :-
Flyer ID - free, but you need to pass an online test, lasts 3 years
Operator ID - £9/year.
If you own and fly, you need both.
These restrictions apply to drones or aircraft weighing between 250g and 20Kg. Below that, it appears to still be unrestricted (though I only looked quickly), and above that .... wrll, if you're operating something above 20Kg, I blooming well hope you already know wgat you require.
There are other exemptions (like only ever flying indoors, under netting, etc) but I suggest if you own or fly anything, you ought to pop over to the section on drones and unmanned aircraft at caa.co.uk and check out what, if anything, you need.
This is, it seems, in effect now.