A 25-year-old man was arrested at the scene on suspicion of grievous bodily harm and possession of an offensive weapon. He was subsequently arrested on suspicion of murder and remains in custody at a central London police station.
Detective Chief Inspector Vicky Tunstall, from the Specialist Crime Command, said: “This is being treated as a random and unprovoked assault and we are not actively looking for anybody else in connection with the incident. I would like to reassure the public that his is not believed to be linked to terrorism.
“It is clear that this area of Oxford Circus was very busy at the time of the attack. Members of the public intervened to detain the suspect and I hope to trace and speak to them, to secure their accounts and offer support. In particular, I would like to trace two young males with skateboards who led this intervention.
“I am appealing to any person who witnessed the assault, or who has mobile phone footage, to contact us. I am also appealing to the owners of any passing cars with dashcams to check whether they have recorded the incident.”