LONDON >> When Cressida Dick left Scotland Yard three years ago, she said she hoped that one day a woman would lead Britain’s biggest police force to show that it was “modern and representative.”

On Wednesday, those hopes were realized when Dick herself was named the first female police commissioner in Scotland Yard’s 188-year-history.

A onetime beat cop in London’s West End, Dick, 56, said she was “thrilled and humbled” by the appointment.

“This is a great responsibility and an amazing opportunity,” she said Wednesday in a statement. “I’m looking forward immensely to protecting and serving the people of London.”

Founded in 1829, Scotland Yard, as the city’s Metropolitan Police Service is known, is the recipient of roughly a quarter of all police spending in England and Wales. (Scotland and Northern Ireland, the other two nations in the United Kingdom, have their own legal systems and police forces.)

The daughter of Oxford academics and a graduate of both Oxford and Cambridge, Dick was head of counterterrorism at Scotland Yard from 2011 to 2014, overseeing among other things the security operation for the London Olympics in 2012.

She left Scotland Yard in 2014 after 31 years to become general secretary at the foreign office.

Dick has held command roles in several counterterrorism operations; one operation went terribly wrong in 2005: She was the senior officer in charge one day after the July 7 bombings in London when Jean Charles de Menezes, 27, a Brazilian who had been mistakenly identified as an attempted suicide bomber in the attacks, which killed 56, was fatally shot by officers at a London subway station.

A jury cleared her of any wrongdoing, but Dick has repeatedly expressed regret.

“I think about what happened on that terrible day very, very often,” she said in 2014.

During the search for a new commissioner, the family of de Menezes wrote a letter to London’s mayor, Sadiq Khan, about Dick’s potential role.

“We have serious concerns about such an appointment and the signal it sends to the people of London,” they wrote.

But Khan and others defended Dick’s appointment.

“This is a historic day for London and a proud day for me as mayor,” he said Wednesday.

Amber Rudd, the home secretary who appointed Dick with Khan’s counsel, called her an “exceptional leader” and implicitly highlighted her gender as a possible asset in some pressing issues facing Scotland Yard.

“The challenges ahead include protecting the most vulnerable, including victims of sexual abuse and domestic violence,” Rudd said. “Cressida’s skills and insight will ensure the Metropolitan Police adapt to the changing patterns of crime in the 21st century.”

Of the 43 police forces in England and Wales, several have been led by women. But never London.

Alex Carlile, a member of the House of Lords, Britain’s upper chamber, who served as an independent reviewer of terrorism legislation, said it was “a very positive thing” that Scotland Yard had women in leadership roles.

“But Cressida Dick has not been appointed because she’s a woman,” he said. “She’s been appointed because she was the pre-eminent person for the job.”

With Dick’s appointment, three of the most senior figures in British policing are now women, with Lynne Owens heading the National Crime Agency and Sara Thornton, one of Dick’s rivals for the Scotland Yard job, the chairwoman of the National Police Chiefs’ Council.

© 2017 The New York Times Company