reporting system used. Based on North/South and East/West lines centred
on the Isle of Wight, the grid comprised 100 Km squares each given a two
letter code, in this example 'uP'. Each 100 Km square was then subdivided
into 10 Km squares and subsequently into 1 Km squares, with numbers used
as per the diagram below. Thus and aircraft position could be referenced
to a 1 Km area by a two letter/four number code, e.g. 'uP2636'.