Am I imagining there being talk here a while back of a second VHF frequency for practice emergencies? Or is that just for UHF Guard?
This would presumably resolve the terrible problems touched on by 30W and Phoenix_x. Mind you, I would think pilots probably want to have a single freq (train as you fight etc).
Personally I routinely listen to lots of VHF/UHF Guard radios (professionally), and I don't think the amount of traffic is significant, though I can understand the odd call may come 'just at the wrong time' for someone expecting a clearance or some such.
I would caution aircraft captains against turning down Guard in UK airspace except in the most extreme circumstances - it may be the only thing saving you having 'company', especially if you miss-dial your route frequency
STH