In the Uk, it is a mandatory legal requirement to wear a seatbelt. Even with todays standard of motor vehicles, most are fitted with Airbags and meet strict crash tests, to improve the possibility of reducing any injury, following a collision.

However, there is NO law, of which stipulates that a motor cyclist must wear protective clothing, other than a CE marked crash helmet.

I want to see this changed with in the UK, where we are seeing more and more motorbike riders and passengers only wearing shorts, t-shirts and open toe footwear in hot conditions. 

it should be mandatory and a legal requirement to wear protective clothing and footwear, while either a main driver and or passenger on a motorcycle.