The Brits had also worked out a method for engaging V2s with 3.7-in HAA. They required warning of a launch and details of the trajectory to be able to work out the point (area?) of impact and TOT. A regiment or more of HAA would then fire a barrage of rounds at a point along the trajectory timed to arrive at the same time as the missile. It never was tried as the Allied advance overran the launch sites, but it just might have worked, if everything had been executed accurately and in a timely manner.