Here’s what I found on wiki no mention of 333. But I can’t believe it wasn’t everywhere in the uk until 1976!
History
First introduced in the
London area on 30 June 1937, the UK's 999 number is the world's oldest emergency call telephone service. The system was introduced following a
house fire in Wimpole Street on 10 November 1935, in which five women were killed.
[12] A neighbour had tried to telephone the fire brigade and was so outraged at being held in a queue by the Welbeck telephone exchange that he wrote a letter to the editor of
The Times,
[13] which prompted a government inquiry.
[12]
The initial scheme covered a 12-mile (19 km) radius around
Oxford Circus[14] and the public were advised only to use it in ongoing emergency if "for instance, the man in the flat next to yours is murdering his wife or you have seen a heavily masked cat burglar peering round the stack pipe of the local bank building."
[15] The first arrest – for burglary – took place a week later and the scheme was extended to major cities after
World War II and then to the whole of the UK in 1976.
[15]
The 9-9-9 format was chosen based on the 'button A' and 'button B' design of pre-payment coin-operated public
payphones in wide use (first introduced in 1925) which could be easily modified to allow free use of the 9 digit on the
rotary dial in addition to the 0 digit (then used to call the operator), without allowing free use of numbers involving other digits; other combinations of free call 9 and 0 were later used for more purposes, including multiples of 9 (to access exchanges before
subscriber trunk diallingcame into use) as a fail-safe for attempted emergency calls, e.g. 9 or 99, reaching at least an operator.
[16]
