This British Standard gives a general introduction to the series of
British Standards specifying single start parallel screw threads of
Whitworth, British Association (B.A.), Unified and ISO metric forms,
the series of British Standards specifying the corresponding screw
gauges with which they are to be used, and the British Standard
specifying the gauge blanks.
BS 8498:2008 history
2008BS 8498:2008 British Standards for screw threads and screw gauges – Introduction and guidance