To be technical, that's too emphatic: it would have been highly improbable or, as a 19th century billiard player would say, a fluke shot (basically, accidental).

...speaking of pedantic. If I'm aiming at something and hit it, it's no accident. No matter how my TI claimed my shots were lucky or that I must have had help, every shot found the target I was aiming at -- it was no accident; it is not the aim for an accidental shot to have struck it's unintended target. If it was decided to continually fire AA over London with the hope that a shot took out a V2 and such happened, it would not have been an accident, however unlikely (and a huge waste of dwindling resources).
To elaborate, we are not disagreeing about your ad-lib point that there was no sure defense against an in-flight V2. Even with today's technology, however, it is not impossible for a rocket to get past anti-missile defenses any more than it's impossible for said rocket to intersect the flight path of a cannonball shot at the steeple of St. John of the Improbable (or whatever).

...but  Andrew, you're neglecting the fact that Charlie also stated "The displaced airflow of the rocket would probably make it unlikely that the cannonball would get close [to] the very fast moving rocket..."
...which automatically eliminates "impossible" without an argument about whether the rocket hits the cannonball or the cannonball the rocket or how effectively the flight paths would be changed for either missile to completely miss their intended targets. Either way, it could well change the outcome of St. John's steeple chase.


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