A 60-year-old man has died after being stabbed in a "random and unprovoked assault" in central London.
The victim was found injured following the incident in Oxford Circus, near to Regent Street, at around 8pm on Thursday and died in hospital.
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.
The force is appealing for people who witnessed the assault, in particular the "two young males with skateboards" who reportedly "led" the public intervention to detain the suspect.
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 this is not believed to be linked to terrorism.
She added: "It is clear that this area of Oxford Circus was very busy at the time of the attack.
Police were called shortly before 8pm on Thursday to reports of a man stabbed at Oxford Circus
"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."
Anyone who can help the investigation is asked to call police on 101 quoting CAD 7129/01Jul, or contact Crimestoppers anonymously on 0800 555 111.
This is a breaking news story, more to follow…