Armed police were deployed to a street outside the BBC Radio 2 studios after a man was stabbed.
The injured 21-year-old reportedly attempted to take refuge in Wogan House during the incident on Wednesday afternoon.
The Metropolitan Police said they were called to reports of a disturbance involving two people in Gildea Street, Marylebone, at 4.25pm, where they found a man with a knife wound to his hand.
"Firearms officers in the area attended the location to support local officers. Nothing to suggest a firearm was seen or used," a Scotland Yard spokesman said.
London Ambulance Service paramedics were called to the scene and the man was taken to hospital for treatment for injuries that were not believed to be life-threatening or life-changing.
Police said they were not treating the incident as terrorist-related
No arrests have been made.