Part of central London has been cordoned off after an explosion in an office building.
What is thought to be a letter bomb detonated in the Capita building near well-known gay venue The Stag in Victoria.
London Ambulance confirmed they have taken one person to hospital.
“Our crews have treated a female patient for minor injuries and conveyed her to hospital. We are still currently on the scene.
“We were called at 9.39 today to an incident in Victoria Street. We sent two ambulances, a duty manager and three support vehicles.”
An area stretching from Westminster Abbey to Scotland Yard remains closed to the public.
Capita runs the Criminal Records Bureau for the government and manages the London Congestion Charge, as well as providing a range of IT and personnel services to public bodies like the BBC.
It is a FTSE 100 company with over 30,000 employees. The motive for today’s attack on one of their London offices is not yet clear.