I'd like to hear how your mini-cooper could smash into an airliner, Leon. Seriously though, it would be interesting to examine the arguments against fitting a standard commercially available TCAS to most (all?) current RAF types. Sure, it won't cope with all eventualities like formation and high g manoeuvres. But it's inexpensive, available now, and is a very useful piece of kit, surely better than waiting for a yet-to-be-invented all dancing version which may never come.