> the location of telephone exchanges was a UK state secret I found myself wondering whether the locations of electricty substations powering critical infrastr

> the location of telephone exchanges was a UK state secret I found myself wondering whether the locations of electricty substations powering critical infrastructure might count as "secret", for instance the three[0] substations that power Heathrow Airport. Obviously one of them isn't secret any more more, having gone up in flames rather spectacularly on 21 March 2025. [0] "Heathrow relies on three electricity substations" https://www.bbc.com/news/articles/c6283577llqo https://www.bbc.com/news/articles/c6283577llqo