See also AD
Air Defence aka Cloud Punching.
Ergo RA Regts who are in AD role are known as Cloudpunchers.
A lesser known role of the RAF Regiment was to conduct Ground Based Air Defence until the Defence White Paper passed all GBAD to the Royal Artillery.
GBAD is only one part of the puzzle - RAF Fighters conduct Air Defence tasks (see Top Gun, The battle of Britain, Angels 1-5 for examples).
The key to the whole Air Defence infrastructure is All Arms Air Defence - this is accomplished by everybody pointing their weapons in the general direction of a fast moving jet and firing.
Notwithstanding reports of US aircraft being shot down by Iraqi insurgents armed with a bolt action rifle the effectiveness of AAAD is not clear. Friendly Forces downrange are generally less than chuffed with demonstrations of AAAD.
Extensive range time is taken up with AAAD shoots using schermulies as targets. Weight of fire and inaccuracy combine to produce an odd alchemy - known as 'turning live into brass'.
There is a school of thought that all AD should be passed over to the RAF. This will accomplish 2 things:
1. All AD is grouped under a single HQ, and as the frontline boys never see the stuff, it may as well go to guard runways, and..
2. It will prevent AD Artillery officers from pretending they're part of the Royal Regiment -bloody jeans-wearing maggots that they are...harrruuuummmmpph!!