Thanks John for helping maintain what remains of my sanity. Conspiracy theories do my head in... that's why I wear a foil lined bobble hat at all times!!!
Steve.
PS I just glanced online and found the following quote on the Wiki and given that OS surveys don't happen that often plus the tower was built in 1966 I would say that it's first appearance on a 1971 Os map was about right.
Wiki quote:
It is often said that the tower did not appear on Ordnance Survey maps, despite being a 177-metre (581 ft) tall structure in the middle of central London that was open to the public for about 15 years.[18] However, this is incorrect; the 1:25,000 (published 1971) and 1:10,000 (published 1981) Ordnance Survey maps show the tower.[19] It is also shown in the London A–Z street atlas from 1984.[20]