When I flew for MON I had to go back 10 years, or until full time education, whichever was sooner. Same applied at EZY.
Perhaps only a LTN thing though, as was based there for both. So nowadays doesn't seem so strict...however I do think that there should be some other element introduced to the security pass application process other than being able to prove you were at such and such a place over the last ten years.
I'm sure it would be quite easy to introduce more rigorous checks however at what financial cost? That's when the beancounters get busy with their scales and work out the cost-v-benefit ratios!!
And who polices the checkers? oh my head is hurting now.....
cheers
FF