A knifeman has been arrested after scaling a 6ft fence into the secure area outside the prime minister's residence in Downing Street.
A man has been charged with possessing a knife and assaulting a police officer during an intrusion into the secure area of the Prime Minister's residence.
Tony Blair was at home when the intruder was spotted at the back of Number 10 on Sunday night, but police said he was not "at risk".
Byung Jin Lee, aged 32, was detained after scaling six-foot-high iron railings at Downing Street on Sunday.
A police officer challenged the man who was arrested after a brief struggle, when a large kitchen knife was found.
Tony Blair was at home during the incident at the back of Number 10, but police said he was not "at risk".
A man is being held on suspicion of affray and assaulting a police officer.
Mr Lee was arrested after a brief struggle and will appear before magistrates on Tuesday.
Scotland Yard confirmed Tony Blair was at Number 10 at the time but said: "We are satisfied that at no time was the prime minister at risk."
Scotland Yard said: "We are satisfied that at no time was the prime minister at risk."
A further layer of security exists between the outer secure area and the garden behind Number 10.
Mr Lee is due to appear at the City of Westminster Magistrates Court.
Security review
The man is understood to have climbed the iron fence in Horse Guards Parade before being tackled by a police protection officer as soon as he dropped onto the other side.
Police said the intruder lunged at the officer, but it is not thought he produced the knife. He was then pinned to the ground while the officer waited for back up.
Scotland Yard said security at the back of Downing Street would be reviewed as a result of the incident.
Doctors are examining the man to establish whether he is fit to be interviewed.
