Driving has to involve risks. By its nature, people travelling to different directions, at different speeds, and with differing amounts of experience on the roads, is going to involve risk. Safe "driving" involves managing those risks, normally by minimizing them to an acceptable level.
The Highway Code number 48 states that..."Safety equipment and clothing. All horse-drawn vehicles should have two red rear reflectors. It is safer not to drive at night but if you do, a light showing white to the front and red to the rear MUST be fitted.
Law RVLR 1989 reg 4"
It is sad to see that people are willing not only to flaunt the Law, but to put other people and animals at risk.
This video was taken on 18th June 2015, on the Gloucester Northern Bypass.