To be fair BPI were pretty good at scaring the absolute shit out of the general British public in the seventies https://www.youtube.com/watch?v=m0xmSV6aq0g&t=2s
The Think! campaign was always pretty on-the-nose, as you need to be sometimes to get these messages across. The seatbelt and in-town speed limit ones stick in the mind too: https://www.youtube.com/watch?v=mKHY69AFstE and https://www.youtube.com/watch?v=jDpOAXfangI respectively.
The memorably stark tone and the frequency they were on TV made these spots ripe for parody, for example this one from Monkey Dust: https://www.youtube.com/watch?v=PsOk9Ln1qOY
My favourite is the one at 1min 30 but all are complete classics here.
https://m.youtube.com/watch?time_continue=105&v=9ciomPP8MyE&...
The one that traumatized me the most as a child was: