A policeman stands guard in front of a building in Victoria Street in central London, Feb. 5, 2007. (Reuters Photo) Photo Gallery>>>

    LONDON, Feb. 5 (Xinhua) -- A woman was slightly injured when a small letter bomb exploded on Monday morning in central London, London police said.

    The Sky News Television reported that a mail bomb exploded at the London headquarters of congestion charge firm Capita, leaving a female employee at the office in Victoria Street slightly injured.

    She has been taken to hospital for treatment.

    "At about 9:40 a.m. emergency services were called to the offices behind us following reports of a small explosion," Police Chief Ian Thomas from the London Metropolitan Police said at the scene of the Capita Group building in Victoria Street.

    Several ambulance, fire engines and police vehicles are parked outside the building. All six floors of the building have been evacuated.

    Bomb disposal experts were also at the scene and Scotland Yard's anti-terrorism command was investigating the incident.

    The Capita Group is a leading business outsourcing company, which collects 25 million payments a year from motorists who pay to use the streets of central London, and television licensing fees.

    The location of the blast is less than a mile from the Houses of Parliament, Victoria Station and Westminster Abbey.