@Double Zero
The 'talk' is that at the last nano-second Al Pollock didn't think he'd allowed for his fin to clear -also he was supposed to be at full throttle - so please allow me for remarking some alarm at this ' stunt '.
From the article referenced in post #31, which purports to be by the pilot himself:
Swiftly I concluded Sydney Camm's favourite fighter would have to fly as close to the top structure as possible. Rather like a reverse skip bombing run with target cues above! At the last split second before I crossed underneath, the steel girders suddenly seemed to explode all about my cockpit, above, below and about my ears, totally engulfing canopy and one's traditional sense of flying fun! That microsecond my mind felt quite certain I had overcooked it and the top span would certainly take my fin off the next millisecond. Something then happened which had only occurred once before to me, when I had mushed after pull-out from an FAC attack with over-sufficient aircraft weight and "g" and insufficient speed, power and thought! Thinking I had hit the ground but missing Cloud Ninety Nine by a whisker, my heart actually had missed a couple of beats with the shock of expected imminent disaster. After that there was the acute, physical reaction as the heart fires up to full stroke again, just like a fighter's fuel pump, trying hard to catch up again. My Hunter flew on, rather unexpectedly finding itself still completely functional and not a finless wonder and I headed out over Greenwich and Hornchurch, heading towards Clacton.