Police are appealing for information after a man was strangled by a passenger in an unprovoked assault while the pair travelled on a bus in the Earls Court area.
Police says 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 suspect's scarf.
It happened at around 13.50 hrs on Saturday 1 December on a bus travelling between Victoria and White City. Police say the attack lasted for around 30 seconds
Police are keen to speak with a black male, in his early to mid 20s. They say he was wearing a grey beanie hat, a sleeveless puffa-style jacket, a beige sweat shirt underneath, dark jeans and dark boots
More top news
In a wide-ranging Peston on Sunday interview, he said Parliament security needs reviewing and the PM's counter-terror strategy is flawed.
The terror attack carried out by Khalid Masood at Westminster that left four people dead lasted less than two minutes say police.
Two knives were found at the scene in Islington, North London, and the suspects fled on foot before being arrested.