[FrightHorse]

When I worked there (2012-2014), we were certainly allowed cellphones, and friends that are still in the IC all still have such devices, so I don't think that's changed. We just (obviously) couldn't bring any electronic devices into the SCIF without specific approval.

Anything with an antenna would pretty much never be approved, but if you wanted to bring, say, a Discman or somesuch, you could check it in, it would be torn apart and checked for anything foreign in the device, and then would be tagged for use in the SCIF. Typically, if something goes in, it's never allowed to leave the building except shredded, mulched, and burned.

[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.