Scripts were written to reassure the public the BBC was "still there"
A script written by the BBC and the government to be broadcast in the event of a nuclear attack has been published.
The script, written in the 1970s and released by the National Archives, included instructions to "stay calm and stay in your own homes".
It said communications had been disrupted, and the number of casualties and extent of damage were not known.
Other papers reveal debates about how to ensure the person reading the script was authoritative and comforting.
The script was discussed from 1973 to 1975, during the Cold War.
'Voice of the BBC'
It was released along with letters between government departments and BBC executives.
The BBC had previously made some of the documents public under the Freedom of Information Act, but this is the first time they have been made widely available.
The Simpsons actor reads nuclear warning
In a letter from June 1974, Harold Greenwood from the Ministry of Posts and Telecommunications discussed who should read the announcement to give it an authoritative and comforting tone.
"During the Second World War we came to recognise the voices of Stuart Hibberd, Alvar Lidell and other main news readers," he wrote.
"I would expect that in the period of crisis preceding an attack a similar association of particular voices with the authoritative 'voice of the BBC' would develop."
Mr Greenwood said recorded announcements by an unfamiliar voice would not reassure listeners.
"Indeed, if an unfamiliar voice repeats the same announcement hour after hour for 12 hours, listeners may begin to suspect that they are listening to a machine set to switch on every hour... and that perhaps after all the BBC has been obliterated," he said.
Adding in live local commentary would reassure listeners they were not listening to a cassette recorder, the Cabinet Office said.
The script said: "This country has been attacked with nuclear weapons. Communications have been severely disrupted, and the number of casualties and the extent of the damage are not yet known."
It instructed the public to turn off fuel supplies, ration food to last 14 days, and conserve water - with a warning not to waste it by flushing the lavatory.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.