An armed officer from an elite Metropolitan police protection unit has been found shot dead, the force has said.
The man was a member of the specialist protection command, a unit whose duties involve guarding past and present prime ministers, their senior cabinet colleagues and foreign dignitaries.
The Metropolitan police said the 43-year-old police constable was found with a gunshot wound on Tuesday at a residential address in Camden, north London.
As part of his duties, he would have been armed with a police issue weapon, and the Met said an investigation into the death would examine whether the firearm used was one issued by the force.
A Met spokesperson said the officer was from a unit separate to the diplomatic protection group, which guards Downing Street and was caught up in the Andrew Mitchell "Plebgate" saga.
The Met declined to say what protection duties the officer had undertaken but said the officer was not under investigation or facing any disciplinary action and that the death was not thought to be the result of a crime. The officer's family have been informed.
Officers went to the address on Tuesday afternoon after neighbours raised concerns about the occupant, the Met said.
"At 16:06hrs on Tuesday 19 February 2013, police went to a residential address in Camden, NW1, following concerns about the occupant. Officers forced entry to the property in King's Terrace and found the body of a man with a gunshot injury,", the Met said.
The Independent Police Complaints Commission has been informed but the investigation will be conducted by the Met's own directorate of professional standards. The Met added: "The death is not being treated as suspicious at this stage ... The investigation will look at whether an MPS firearm was involved."
An inquest has been opened and adjourned.
Officers who volunteer to carry firearms are vetted to see if they are suitable.