Mountain bike helmets

There’s always lots of controversy around bike helmets. Mention the words “bike” and “helmet” in the same sentence and opinion will immediately be polarised quicker than you can say the word “Brexit”!
Surely though,  it’s a given that you wear one if you’re mountain biking? – but what’re the best options available right now?
See here for the hotest deals on the best MTB helmets: https://buff.ly/3bK21cy