I think this goes back to the two definitions of "British" that we had that other long thread about, Keith. That REALLY, REALLY long thread. Did I mention how long it was?! No interest in revisiting that anytime in the near future as I've got enough headaches to deal with at the moment :)
Keith, as far as judging success by numbers of fatal casualties, I've actually never thought about considering that. To be honest, I'm sure you were very much trained like I was because our armies are so similar that a mission's success is determined by several things, but, for me and my troops one of those things has never been body count. So, as far as the PIRA having the label as being "the most successful," it has more to do with the lifespan of the organization, its adaptability, recruitment, and things of that nature that kept it running since 1969. Though, yes, I do understand some missions did center around people-targets vs. physical targets, and that those particular missions were deemed successful if their purpose was completed. I suppose that after hearing from several historians and instructors of military history that the IRA was the most successful guerilla in history, I did assume (which I know I should never do) that there would have been more deaths attributed to them.