Since then, detectives have contacted nearly 2,000 witnesses.

They’ve also watched 2,200 of CCTV footage and collected 1,200 exhibits, but haven’t interviewed a single person under caution.

The force is particularly interested in a black Volkswagen van seen in the area.

Commander Richard Smith, head of the MPS Counter Terrorism Command, said:

 “This has been a hugely complex, challenging investigation from the outset. Officers have taken hundreds of statements and collected a large amount of evidential material, but so far no arrests have been made.

“Three years have passed and we are again asking the public, particularly people who live in or visit the New Malden area, to cast their minds back to 12th of March 2018. Did you see a black Volkswagen van in or around Clarence Avenue that day? Did you see anything that in retrospect was unusual or suspicious? Anything you can recall might be crucial to our investigation.”

Since the investigation was launched, detectives have contacted over 1,800 witnesses and taken more than 420 statements.

Officers have also viewed 2,200 hours of CCTV footage, and 1,200 exhibits - including forensic samples, as well as physical items - have been collected as part of the investigation.

Detectives have made no arrests during this investigation, nor has anyone been interviewed under caution."

Anyone with information is asked to call 0800 789 321 quoting Operation Bulblet. 

Alternatively, call independent charity Crimestoppers anonymously on 0800 555 111.

Mr Glushkov was a retired financial director who had lived at the address in Clarence Avenue for two years.