Knifeman held at Blair's London residence

LONDON, Oct 2 (Reuters) An intruder armed with a knife was arrested after scaling a wall and getting into a secure area of British Prime Minister Tony Blair's official London residence, police said today.

The man was apprehended after he scaled a fence from a road open to the public at the back of 10 Downing Street into what officials describe as the building's outer secure area.

''As he got to the other side he was immediately challenged by an officer and arrested following a short struggle,'' a London police spokesman said.

Although the man was found to be carrying a knife, described by media reports as a large kitchen knife, police said they did not think the incident had any terrorism link. The man's motive was not yet clear.

''We are satisfied that at no time the prime minister was at risk,'' the spokesman said.

The man was arrested on suspicion of affray and assault on a police officer and was taken to a central London police station for further questioning.

There was no comment from Blair's office. The BBC reported the prime minister was at the property at the time.

Police said a review into security arrangements would be conducted.

Number 10 Downing Street is traditionally the London home and office of the prime minister, although Blair and his family live next door at number 11.

Security surrounding Downing Street has been intensified in recent years. The road, which lies between the Houses of Parliament and Trafalgar Square, has been closed to tourists for years.

Instead they can peer through the 10-metre gates, erected during the premiership of Margaret Thatcher in 1989 and guarded by heavily-armed police, for a glimpse of the famous front door.

The street came under attack in February 1991, when the Irish Republican Army (IRA) fired mortar bombs at the 10 Downing Street office when former prime minister John Major and his entire cabinet were inside.

The shells exploded in the garden, close to the cabinet room, but no one was injured.

REUTERS LL KN1939