Check out the (apparently authentic) script that BBC news readers were to use should a nuclear attack ever have been launched at Britain. (You will need Adobe Reader or another application capable of displaying PDF files to read that link.)
Although the BBC article mentions that the script was written back in the 70s, it does not mention when it was deemed un-necessary or too dated – is there likely to be a replacement that we will not hear (hopefully) for another 30 years, or given that the (original) cold war is over, do we simply not have an alternative plan for the BBC et al?