Crass – known for releases such as "Nagasaki Nightmare" and "Penis Envy" – undertook a variety of anti-establishment protests during the late 1970s and early 1980s.

None were more successfully subversive as when, in 1982, the band spliced together recordings of British Prime Minister Margaret Thatcher and US President Ronald Reagan to make it sound as though they were arguing over the Falklands War and discussing the possibility of launching nuclear weapons at Germany.

Crass then posted the tape to Dutch newspapers, who swiftly dismissed it as a fake. But a few months later the US State Department got hold of a copy and loudly proclaimed it to be an example of underhand Soviet Union propaganda.

Official UK government documents, declassified for the first time today, show that Margaret Thatcher was kept updated on the incident by the Foreign Office. The papers also suggest that MI6, the CIA and the US State Department were in communication with each other regarding the tape for up to two years.