The Met was called to assess a "suspicious vehicle" near Buckingham Palace on Friday afternoon.
Westminster Police was called to Constitution Hill just after 1.30pm.
But it was deemed non-suspicious about an hour later.
The force said in a statement: "The vehicle in Constitution Hill, SW1, has been deemed to be non-suspicious.
"The incident has now being stood down and cordons are in the process of being lifted. Thank you for your patience."
