oh yes... the same era that the high security, guards all-over-the-place cameras-everywhere security-doors-heavy-enough-to-take-limbs-off military equipment R&D company I worked for at the time, was broken into by the local scrotes for memory boards from the PCs... They just cut the fence, walked across the grass no-man's-land and jemmied a window...
They even had time to carry all the PCs from the office areas to each wing's lab areas to use the company's tools and anti-static mats... They did get disturbed in the end, and 1 guy caught due to a broken leg, after he forgot he wasn't on the ground floor.
Explaining the incident to the UK MoD was "interesting", as were the repercussions for the site.