I have a simmilar story - I was working for now-defunct Carillion, we were doing a load of new build work on a north london military base. They couldn't / wouldn't provide any ug services drawings for security reasons, so every time the excavators / groundworkers hit a cable or pipe, we had to tell the base, they made everyone go away and their own Royal Engineers teams erect a massive shield around it to hide the action, fixed and / or reburied it but in secret location elsewhere.
I have a simmilar story - I was working for now-defunct Carillion, we were doing a load of new build work on a north london military base. They couldn't / wouldn't provide any ug services drawings for security reasons, so every time the excavators / groundworkers hit a cable or pipe, we had to tell the base, they made everyone go away and their own Royal Engineers teams erect a massive shield around it to hide the action, fixed and / or reburied it but in secret location elsewhere.