The UK law is currently under review. The guidance on the Government website is “You should wear a cycle helmet when using an e-scooter. Helmets are recommended but are not a legal requirement.”
I recently carried out an informal survey* on whether helmets should be compulsory in the UK. The vast majority (47 out of 50) were for.
My own view is that the aim of the game is to not only protect yourself but to make yourself as visible as possible when you are riding an e-scooter on the road (think bright lights and neon clothing).
As someone who sees the bitter consequences of severe road traffic accidents, I am a keen advocate of taking safety precautions wherever possible. While there will always be people who do not comply with the law (the owners of private e-scooters who ride them on public roads and pavements come to mind), if a helmet can save just one person from suffering a traumatic brain injury, then it will be worth it. I am therefore for compulsory helmets for e-scooters.
*Poll of 50 votes from LinkedIn contacts **From 2009 to 2019 – study conducted by the Henry Ford Health System.