Re: The definition of insanity
It's worth bearing in mind that this was in the aftermath of the dotcom collapse, when BT's share price dropped from ~£10 to the £2-£3 level (and where it's languished ever since). From a beancounter perspective, drastic measures were needed, and the property portfolio was an easy target.
Then too, presumably, part of the calculation was based around the fact that they were reducing headcount at the same time, so fewer buildings were needed and they could let the leases lapse. Back in the late noughties, the building I was working in had an entire floor mothballed, while the local BT building was even emptier; it's since been sold off altogether and turned into student accommodation.