1. . It was first used in English in the 1800s.

2. In Discipline and Punish, his 1975 work on "disciplinary regimes" such as torture, imprisonment and other forms of criminal justice, French historian Michel Foucault dates the concept of modern surveillance to the "panopticon". This was the utilitarian philosopher Jeremy Bentham's idea for a prison in which all the prisoners were visible at all times from a single vantage point. (Bentham was writing in the 1780s.)

3. Electronic surveillance began during the American Civil War, when the rival sides tapped into each other's telegraph messages.

Read more

Spy wars: South Africa is not innocent
SA knew UK was spying on it in 2009
Law cannot keep up with spying tech
Spying: SA's outcry over spying rings hollow

4. The BBC reports that, according to its own government-mandated information commissioner, Britain is now officially a "surveillance society", with a closed-circuit television camera for every 14 people in Britain.

5The notion of constant surveillance of all members of society was first imagined in the novels of Yevgeny Zamyatin (We, 1920) and George Orwell (Nineteen Eighty-Four, 1948) – the latter invented the term "Big Brother" for the ­surveillance state. It became a characteristic of the totalitarian regimes of the Soviet Union and its Eastern European satellites.

6. East Germany under communist rule developed the most complex and comprehensive of surveillance systems. Apart from personal spying, which employed about half a million people and relied on at least 1.5-million regular informants, the ministry of state security (Stasi) had an extensive electronic-surveillance network. The 2006 movie The Lives of Others, an Oscar-winner for best foreign film, explored the psychological devastation that occurs to people living under such a regime.

7. Other movies about surveil­lance include The Conversation (Francis Ford Coppola, 1974), Blow Out (Brian de Palma, 1981), Brazil (Terry Gilliam, 1985) and Enemy of the State (Tony Scott, 1998).

8. Wiretapping or the interception of telephone calls was declared constitutional in the United States in 1928, when the use of phone­tapping was challenged in the trial of boot­legger Roy Olmstead.

9. It was only in 1967 (a Supreme Court judgement) and 1968 (a Senate vote) that it became law in the US that wiretapping or other interception of communications required a warrant from a judge. Later laws, citing national security and so forth, found ways to evade such strictures. They are now highly contested in cases such as the Prism surveillance programme.

10. The Watergate scandal, which brought down US President Richard Nixon in 1974, had to do with his and his supporters and party's spying on opponents and others. In the White House, many conversations were recorded. Of the recordings featuring Nixon himself, 18.5 minutes of one tape were erased and never recovered.