I wonder if it is still the case that the French military and civil ATC staff don't talk to each other and co-ordinate what is going on in the sky.
If so then I expect a lot of these 'intercepts' might be avoided since the civil authorities would know what the track is and whether it is in communication or not.
The fact is that even at supersonic speed, intercepting a civil A/C at F350 somewhere around the FIR boundary when your base is Cambrai would take around 10'. Add an extra 10' for the chain of command and time to start/taxi/T/O and you end up with something like 20'==> 150NM travelled by the cookie at M.75 average!!! This is why the intercept is started BEFORE FIR boundary sometimes...
The timing logic is sound, however, why would you set up an intercept for something that is probably in legitimate contact with an adjacent state and has not been transferred yet ? A flight that is going about its legal business without problem in international airspace. Or do the air defence people operate on a quota per day and miss a bonus payment if they don't tally the required number of civil (British) airliners ??
