London's Metropolitan Police Service, better known as Scotland Yard, is Britain's oldest and biggest police force. More than 43,000 officers and staff work for the organization.
On Wednesday, Cressida Dick, 56, was named as the first female police commissioner in the organization's 188-year history.
In a statement, the former beat cop from London's West End, said she was "thrilled and humbled" by the appointment.
From 2011 to 2014 Dick was head of counterterrorism, and among other operations, she oversaw security for the 2012 London Olympics.