Crosschecking various records seems to imply that my FIL signed up before he was required to do so. Apparently born 4/1922 in Glasgow, by 12/1940 (therefore 18 and 10 months) he was apparently a gunner in the Royal Artillery. Under the various Government Acts at that point the youngest age being called up was 20. How/when/why would he have signed up? How often did this happen? Was it considered a way to get out of a dead end area and open new horizons?