You can't be certain- you can be ready. Join your local Special Constabulary, ask at any police station.
England, C. 194230 x 20 in (76 x 51 cm)
ID #SMALLWARTBL-J-710
English War Poster.
30 x 20 in (76 x 51 cm)
ID #SMALLWARTBL-J-710
English War Poster.