Police have released CCTV footage showing the moment a man was strangled with a scarf on a bus in London, in a seemingly unprovoked attack.

Police are appealing for information after the 30 second attack, which took place on Saturday 1 December on a bus in the Earls Court area.

They say the assault was so fierce that the victim, a 37-year-old man on his way to work, passed out as he was being choked with the item of clothing.