Ah Public Safety films
YouTube - Apaches - Horrific UK Public Information Film - Part 1
YouTube - Scary 1970s British Public Information Films
We were subjected to them on the school's projector.
I remember the one called Building Sites Bite with its hapless hero being killed bloodily over and over again.
I'm afraid these films failed on me as I couldn't wait to rush over to the nearest building site (where I died bloodily).