I think a pudding basin with a BSI mark is still legal in the UK. I stopped wearing mine after I fell off and landed on my head. Surprisingly the helmet did its job well, but the dent in it and the blood all over it from a cut to my forehead put me off using it again.
Ariels - 1913 TT Model, 20 Roadster, 28 Model D, 30 Model B, 38 VH, 52ish VH
The Offroad Fleet - Fantic 200, Bultaco Pursang, Beta Rev 3