[nul_byte]

They are not allowed at GCHQ. I once visited CESG , and was told to leave laptop and phone in the car or at the desk. I spoke to one of the guys working there about 'how did he find it without having a mobile', and he replied that it was actually quite nice as they did not get disturbed too much. They do have pagers that allow them to be reached, to then find a desk phone and call back.

[FrightHorse]

Ah, sorry, that's what I meant to imply. NSA has the same policy. I took the poster's meaning to be no phones at all. I always left any electronic devices at home.