If this takes place, which I'm hopeful it wont, but if, then every GA airplane in the UK should go up with XPNDR turned off and bust that airspace. I would like to see the CAA try to sort a hundred infringements out, or furthermore, try to prosecute that. Fat chance of backing any allegation up with evidence in such a case. A bit of civil disobedience does democracies good once in awhile.
But honestly, as someone said - if you really had bad intentions, which RAF scrambling aircraft would that be that could intercept an aircraft before it got to its target from outside the zone? It's utter madness. Nobody could reasonably intercept that, assess the situation, define if they're friend or foe in the time it takes to fly a couple of NM. Even if the interceptor was already airborne, in that quadrant and had the fastest aircraft known to man, could they achieve this.