Staff in the bank were moved to safer sections of the building, while workers in nearby offices, including NatWest where a Mortgage Introducer Round-table was being held, were told to stay away from the windows of their premises.
Delegates to the Round-table and staff based in the Princes Street offices were evacuated to the basement of the building.
Robyn Hall, publishing director of Mortgage Introducer, said: “It was a very strange incident. It's hard to understand why someone would abandon a vehicle in the heart of the City.”
Deputy editor Ryan Fowler added: “It was a worrying moment. When you are locked in the basement of a building it’s hard not to be worried.”
Delegates at the Round-table included: Jon Round, LSL; Andy Trantum, Embrace Mortgages; Nigel Stockton, Countrywide; Peter Williams, Simply Finance; John Cofield, Paradigm; Adrian Scott, Connells; Lea Karravvasas, Prolific; Paul Kane, NatWest Intermediary Solutions and Dave Toulson, NatWest Intermediary Solutions.