Ideal for a met office, no windows and bombproof
The AlterMets were thus handicapped/ advantaged on the hardened RAF airfields. Often in the AlterCOC as I recall.
The joke was that, as and when we occupied AlterMet, the airfield soft office was abandoned so certain senior RAF officers began asking "so, all your eggs are in one basket, what about an alter-alter as backup?".
I think it was SMetO Brueggen who brightly suggested using the soft office, sir.