SFO,
that'd guarantee a huge shot to foot I suspect - which, admittedly, HAS tended to be the RAF
PR dept's primary target for longer than I care to remember.
JFZ - I get your point re ignition, but I wouldn't blame that rather than the fuel leak. To my mind there was a source of ignition present for a long time, it didn't cause a fire because fuel wasn't also present. Unless I'm mistaken, and allowing for the absence of complete certainty in all this, the actual catalyst would appear to be the tanker type - as previous tankers used, such as the Victor, VC10 and Herc, didn't produce the same pressures... a case of it all actually being unsafe for years I suspect, but it was only when the final piece fell into place that the clock started to tick because finally pressure spikes started to occur that exceeded the systems ability to cope - and nobody seems to have known what pressures were being reached, and what the safe limit the system could handler were. (For anyone wishing to howl at this last sentence, I'm suggesting that both pieces of info were essential for safe operation, and that they weren't actually known - it was just assumed that everything would still go okay).
That may well all be a simplification, or just plain wrong...as I said, I too am struggling to understand it all.