Question: Cressida Dick was the first what to become head of London's Metropolitan police department?

Context articles: Metropolitan Police Department, City of St. Louis
Municipal Integrated Emergency Response Team
Commissioner of Police of the Metropolis
Charlotte-Mecklenburg Police Department
Real Time Crime Center
Savannah-Chatham Metropolitan Police Department
Cressida Dick
Metropolitan Police District
Cathy L. Lanier
Metropolitan Police Authority

The Metropolitan Police Department (SLMPD) is the principal law enforcement agency responsible for serving City of St. Louis in the U.S. state of Missouri.
 The department is accredited through the Commission on Accreditation for Law Enforcement Agencies (CALEA).
 The current Interim Commissioner of Police is Lieutenant Colonel Lawrence M. O’Toole, who was named to the position on April 19, 2017.
 The Metropolitan Police Department is a division of the St. Louis Department of Public Safety.
 Metropolitan Police Department is the second largest city police agency in Missouri, based on number of employees, city population, and geographic area served.
.
The Municipal Integrated Emergency Response Team (MIERT) was an emergency response unit formed as a joint venture of police agencies in the Lower Mainland of British Columbia, Canada.
 It was formed in 2006 and is composed of members of the Delta Police Department, the Abbotsford Police Department, the New Westminster Police Service, and the Port Moody Police Department.
 In 2013 the MIERT was disbanded and the Abbotsford Police Department formed its own Emergency Response Team.
 The remaining services have decided to either combine or contract their teams with the Vancouver Police Department (Delta Police Department, Port Moody Police Department) or contract with the Royal Canadian Mounted Police (New Westminster Police Service).
The Commissioner of Police of the Metropolis is the head of London's Metropolitan Police Service.
 The post is currently held by Cressida Dick, who assumed office on 10 April 2017.
The Charlotte-Mecklenburg Police Department is the police department of the City of Charlotte & Mecklenburg County, North Carolina, US.
 With 1,849 officers and 473 civilian staff as of 2014, covering an area of 438 sqmi with a population of nearly 900,000, it is the largest police department between Washington D.C. and Atlanta, Georgia.
 The CMPD is unique in that it was formed in 1993 with the merger of the former Charlotte City Police Department and the Mecklenburg County Rural Police Department.
 Mecklenburg and neighboring Gaston County were the two counties out of the state's 100 counties to have county police in addition to the sheriff's offices.
 County police perform law enforcement tasks in the county with police powers anywhere in the county just like the sheriff, but the sheriff primarily handled the courts and jails.
 The North Carolina General Assembly approved legislation combining the two agencies.
 They are by statute "county police" in that they have jurisdiction anywhere in Mecklenburg County.
 However currently, the CMPD does not have any response areas outside Charlotte but within Mecklenburg County.
 The unique status of this situation makes the CMPD "metro" police, and the City of Charlotte has no municipal police department.
The Real Time Crime Center (RTCC) is a centralized technology center for the New York (NYPD), Miami-Dade Police Department, Seattle Police Department, Metropolitan Police Department, City of St. Louis and Houston Police Departments.
 Its purpose is to give field officers and detectives instant information to help identify patterns and stop emerging crime.
The Savannah-Chatham Metropolitan Police Department is the primary law enforcement agency for the city of Savannah, Georgia, United States, as well as Chatham County, Georgia.
 It was founded in 2005 when the Savannah Police Department and the Chatham County Police Department merged.
 The Chief of Police is Joseph H. Lumpkin, Sr.
Cressida Rose Dick, {'1': ", '2': ", '3': ", '4': "} (born 16 October 1960) is a British senior police officer, currently the Commissioner of the Metropolitan Police in London.
 She is the first woman to take charge of the service, being selected for the role in February 2017 and taking office on 10 April 2017.
The Metropolitan Police District (MPD) is the police area which is policed by the Metropolitan Police Service in London.
 It currently consists of the Greater London region, excluding the City of London.
 The Metropolitan Police District was created by the Metropolitan Police Act 1829 as an ad hoc area of administration because the built-up area of London spread at the time into many parishes and counties without an established boundary.
 The district expanded as the built up area grew and stretched some distance into rural land.
 When county police were set up in England the forces of Essex, Hertfordshire, Kent and Surrey did not include those parts of the counties within the MPD and Middlesex did not have a county force.
 Similarly, boroughs in the MPD that elsewhere would have been entitled to their own police force did not have them.
Cathy Lynn Lanier (born July 22, 1967) was the chief of the Metropolitan Police Department of the District of Columbia (MPDC).
 Lanier was appointed by Washington, D.C. Mayor Adrian Fenty in January 2007, replacing outgoing Police Chief Charles H. Ramsey.
 She is the first woman to achieve the position.
 In May 2012, Mayor Vincent C. Gray agreed to retain Lanier as police chief under a new five-year contract.
 On August 16, 2016, it was announced that Lanier would retire from the Metropolitan Police Department of the District of Columbia in September 2016 to become Senior Vice President of Security for the National Football League.
 Her last day as Police Chief was September 15, 2016.
The Metropolitan Police Authority (MPA) was the local police authority responsible for scrutinising and supporting the work of the Metropolitan Police Service, the police force for Greater London (excluding the City of London Police area).
 The establishment of the MPA in 2000 marked a fundamental change in the policing of London; establishing, for the first time, a local police authority for the metropolis, with the aim of ensuring that the Metropolitan Police Service was democratically accountable.