NUMBER THEORY
- Paul Hansbury
- 2 days ago
- 5 min read
Imagine there has been a nuclear attack on the United Kingdom. One of Britain's four nuclear-armed submarines is at sea, in line with the country's policy of maintaining a 'continuous at sea deterrent', and its communications to the mainland have been lost.
The submarine commander needs to know how to respond. It is popularly believed that the standard procedure includes checking whether Radio 4 is still on air. In the absence of a broadcast, the commander is to assume that London has been hit and the government incapacitated. The commander's task now is to open 'the letter of last resort', a set of instructions written by every prime minister when they take office for just this situation.
The letter of last resort tells the commander what to do next. It could instruct the commander to launch a nuclear missile in retaliation; more likely it will instruct the commander to take orders from an ally (almost certainly putting Britain's nuclear weapons under the control of the United States); I suppose it could say 'Do nothing'.
I do not know whether the Radio 4 test is actual procedure. Regardless, my point is that, even in our technologically advanced era, low-tech matters. Radio matters. Signals can be jammed, for sure, but communicating by radio remains reliable. Shortwave radio has the advantage that it can be transmitted over large distances; for this reason it has been used for international broadcast services like the BBC World Service, as well as for diplomatic and military activities.
The numbers never ceased
Earlier this month, some radio enthusiasts in Italy tuned in to a shortwave radio frequency to hear strings of numbers being read aloud in Farsi. The listeners believe that the broadcasts, which continued daily, were CIA codes, instructing agents in Iran as part of the US-Israeli military campaign launched on 28 February.
Numbers stations, as such mysterious broadcasts are known, peppered the airwaves throughout the cold war and since. The general understanding is that they are used by intelligence agencies to communicate with agents in the field, who decode the message conveyed in numbers (or some other form of code), although no one is on record confirming their exact purpose as far as I know.
