Counter-terror police are treating the death of 68-year-old Russian businessman Nikolay Glushkov as murder, Scotland Yard said.

Scotland Yard said a post-mortem examination found that Mr Glushkov's cause of death was "compression to the neck".

The businessman was a close friend of Vladimir Putin critic Boris Berezovsky.

The Met added: "At this stage there is nothing to suggest any link to the attempted murders in Salisbury, nor any evidence that he was poisoned."

Mr Glushkov's body was found at his home in Clarence Avenue, New Malden, south-west London on Monday but police said at the time his death was "unexplained".