Re: "used drones to observe the Ukrainians' movements"
it's alarming a 25 year old technology don't have proper countermeasures....
There are appropriate countermeasures, mostly systems around the Oerlikon 35mm gun. The UK's Oerlikon GDF was retired due to budget cuts at the end of the cold war (havng been acquired via nicking them from the opposition during the falklands war) and is now in storage in the UK. Marconi developed the Marksman anti-aircraft system to stick 35mm guns on a tank, which Poland bought.
So if we wanted or needed a system to shoot down drones then we can dig up the existing systems from storage and train people on them, or buy new ones from Marconi and train people on those. More pressing questions would realistically be what purpose our army is equipped for. Fighting the Russians seems to be in vogue again, so let's consider that for a moment.
Our army has 227 tanks, plus 181 in reserve. The Russians have the following types and numbers of tanks:-
T14 MBT- 100 active
T90 MBT 350 Active 200 in reserve
T80 MBT 450 Active 3000 in reserve
T72 MBT 1900 Active 7000 in reserve
It should be immediately obvious how inadequate our little army would be/is for fighting Russia.
IMO: Britain has no place fighting a land war against pretty much anybody unless they are trying to cross the channel, and we'd be better off nationally having a smaller army but with lots of equipment in reserve. This means that we can relatively quickly ramp up the army in response to a crisis, but we don't have a standing army which our politicans can use to invade other countries because they want to look big on the international stage.
We can then have a defense policy around having a larger navy to protect our trade (as evidentely we don't have the ships to protect it against pirates in speedboats with AK's at the moment) with a large and well equipped airforce. We'd then be able to contribute a usefully large and powerful airforce and navy taskforce to international operations instead of sending an inadequate number of illequipped troops.