Officer Punched in the face after £17k worth of nitrous oxide canisters seized at Notting Hill Carnival

This weekend at Notting Hill Carnival, over 3,500 nitrous oxide canisters have been seized by police. The canisters have a street value of over £17,000.
This afternoon, an officer on patrol in Lonsdale Road, W11 was in the process of seizing 400 canisters from a man engaged in alleged illegal street trading. 

Whilst being processed, the man attempted to run away. He was detained and punched the officer in the face. The officer sustained a dislocated nose, split lip and swollen knee.
After treatment by medics the officer resumed his duties.
One man has been arrested for ABH. Investigations are ongoing.
Investigations into the nitrous oxide canisters have been referred to Trading Standards officers from Westminster City Council and the Royal Borough of Kensington and Chelsea.