My Dad (2nd from left) wearing his flat cap at the British Industries Fair, Castle Bromwich. in 1948.
I have commented on another thread about my mother saying that as a girl she had to run back home for her hat while the church bell was still ringing because she had to pass her grandmother's house and she knew that her dad would get told off if her grnadmother saw her on the street without a hat.
I think that the film which started this thread was in Belfast and surounding areas.
For a Birmingham photo, look at all these business men in the 1930s going into the British Industries Fair, a predecessor of the NEC