At risk of getting shot down in flames, I have seen both 'Run and Break' and the more standard 'civil' joining procedures. IMHO that neither is inherently more risky than the other. The key aspect in both situations is that everyone knows and plays by the rules. From a military perspective, there is no better way of expeditiously joining the cct, fitting into the pattern and then landing. It is safe, expeditious and minimises noise footprint.
Picking-up on the previous noise footprint point, I once saw a VC10 do a run and break at a particularly environmentally sensitive German airfield. Ordinarily, the Ten would have peaked the noise meters at about 95db when dragging itself along on a 3deg ILS; the run and break produced 82dbs.
Regarding the North Weald incident, I find it quite astounding that anyone can relate a properly performed run in and break with this mid-air.