© Scott D'Arcy/PACordon in Westminster where police said they shot and killed a man who was armed with knives.
Officers from the Metropolitan police remained overnight at the scene of the incident which occurred at around 11.30pm on Sunday. Road closures were put in place.
The force tweeted: "A man has been shot dead by officers following an incident in #Westminster at 23.27hrs on Sunday 8 March. This is NOT being treated as a terrorist incident."
The man shot dead by police in Westminster was "acting suspiciously" and produced two knives when challenged by officers, police said. Armed officers responded by firing a Taser and a gun.
The man was pronounced dead at the scene a short time later. No police officers or members of the public were injured, the Met said.
The shooting is understood to have happened in the Whitehall area of London, which is packed full of sensitive government and official buildings.
Under the law, any shooting by the police has to be independently investigated by the police watchdog, the independent office for police conduct.
Comment: Details surrounding the incident are still emerging and exactly why they were compelled to shoot the man dead - normally a choice of last resort for police in the UK - has yet to be revealed.
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