Thank you very much! That certainly explains everything, although it is incredibly hard to visualise how the airport looked with separate security entrances to each pier rather than a central security area.
I think I've only been through Glasgow once since the "new" layout, and that was about 10 years ago, so if anything I recall the old layout better than the current one with its huge security area and duty-free. Did the building get extended to form that space? If not, it might just have been an empty area above the check in hall and domestic arrivals. I remember the old layout as being more airy and spacious.
If I've got my history right, the Central Pier was built as part of the original 1966 building, then extended in the early 1970s to provide a base for the London shuttles for BA.
In my time BA mainly used the gates around the triangular area at the north end of the pier. There was (possibly still is?) a small BA Exec Club Lounge on the east side. It used to get so full that I rarely used it even when I had a ticket that qualified me to do so.
Was it the case that it was just a small security facility? I remember Aberdeen in those times, and it wasn't much more than a couple of simple scanners and a metal detector doorway.
I'd guess it was no more than about 25m long by 10m wide, maybe less. I think just two scanners at the far end, with an option to fill the rest of the space with a zigzag queue. I usually went through at about 7pm, by which time there would probably only be a Birmingham, a Gatwick and a couple of Heathrows left to go, so it was normally straight through with no queue. On the occasion I almost got caught out, the whole room was full of the queue - fortunately BA had staff there calling forward passengers whose flight was near to closing, so I was allowed to skip most of the queue. I didn't find out what had caused the problem.
Some other random memories:
I'd flown up to Glasgow on the morning before the 9/11 attack on New York. On my return two days later, there were extra security checks set up at each gate, immediately before boarding the aircraft. I think they'd gone again by the following week though.
On one occasion several successive Heathrows, including mine, had been cancelled, and the gates area was heaving. About 9pm BA sent up a wide body, probably a 767, which successfully hoovered up several flight's worth of passengers. It's the only time I remember seeing a wide body there. 757s were common at one time though.
Another occasion Heathrow was on strike with all flights cancelled. I was offered either Birmingham or Southampton plus a minibus transfer. I chose Southampton, meaning the minibus to LHR went quite close to my house. No benefit though, as I still had to recover my car from Pink Elephant at Heathrow.
