My daughter was involved in a road traffic accident and was wearing a helmet. She suffered a skull fracture but has been told by neurologists this would have been 10 times worse or even fatal, had she not been wearing a helmet. Thankfully she has made a good recovery but it could have been so much worse. 

4,000 cyclists were killed or seriously injured in 2017 & 70% of these suffered serious head injuries. 

Wearing a helmet will save lives and reduce serious head injury. 

Teenagers are particularly reluctant to wear a helmet and making it law takes away this choice thus reducing the risk that not wearing a helmet poses.