The 1951 Festival of Britain had 2 interesting towers.
The web got additional information on the Skylon,
- Skylon Tower/Vertical Feature at the Festival of Britain 1951 in Dominic’ Pics
- Skylon described in Tensegrity
- Skylon Tower page in Wikipedia
The other tower on the Festival site was the Shot Tower. Again through the wonders of the internet here’s all about it, In the photo from Terry Whalebone’s Flickr site, shows the Shot Tower on the left.