ON a day when Boris Johnson tore up all the diplomatic forms and effectively accused Russian president Vladimir Putin of assassination, police declared that the death of anti-Putin Russian businessman Nikolai Glushkov in London last weekend was murder.

Adding yet more intrigue to an already complex mixture of claim and counter-claim over the attempted murder of former spy Sergei Skripal and his daughter Yulia, Glushkov’s death was declared to be murder by “compression of the neck”.

The former deputy director of Russian airline Aeroflot was given political asylum in the UK in 2010 having been jailed on fraud charges in his homeland in 1999. He was due in court this week to face a commercial claim for £123 million from Aeroflot.

Glushkov, 68, was a noted critic of Putin and a close friend of fellow Russian businessman Boris Berezovsky, who also came to the UK after falling out with Putin. Berezovsky apparently hanged himself in 2013, but the coroner recorded an open verdict.

Former world chess champion and Russian opposition leader Garry Kasparov said yesterday he was “not surprised” that Glushkov was murdered, and hinted at a link with the current investigation into President Donald Trump’s ties to Russia, being examined by special counsel Robert Mueller.

Kasparov said: “I think this is a message addressed to Russians with significant interests abroad who are thinking of co-operating with Robert Mueller. It’s a pre-emptive strike. Tragically it’s not even about Glushkov. They pick someone who is expendable and recognisable.”

The Metropolitan Police issued the following statement about Glushkov: “Police were called by London Ambulance Service at 22:46hrs on Monday, March 12, after Mr Glushkov was found dead at his home in Clarence Avenue, New Malden.

“Officers attended and an investigation was launched into his death, which at that stage was treated as unexplained. A special post mortem began on Thursday, March 15, and we received the pathologist report today (Friday, March 16), which gave the cause of death as compression to the neck. His family have been informed.

“The Met Police’s Counter Terrorism Command, which has led the investigation from the outset, is now treating Mr Glushkov’s death as murder. As a precaution, the command is retaining primacy for the investigation because of the associations Mr Glushkov is believed to have had. At this stage there is nothing to suggest any link to the attempted murders in Salisbury, nor any evidence that he was poisoned.”

Glushkov’s killing is also to be investigated by the Russian authorities – their Investigative Committee has opened a criminal investigation into the attempted murder of Yulia Skripal, and what it said was “the murder” of another Russian in Britain.

Boris Johnson, meanwhile, has already found Vladimir Putin all but guilty of ordering the attempt on the lives of the Skripals. The Foreign Secretary said yesterday morning: “Our quarrel is with Putin’s Kremlin, and with his decision – and we think it overwhelmingly likely that it was his decision – to direct the use of a nerve agent on the streets of the UK, on the streets of Europe, for the first time since the Second World War.”

Putin’s government responded very strongly. Presidential press secretary Dmitry Peskov told the state-run Tass news agency: “We have already said on many levels that Russia has nothing to do with this story whatsoever.

“Any reference or mention of our president in this connection is nothing but a shocking and unforgivable violation of the diplomatic rules of propriety.”