Question: Operation Kratos referred to tactics developed by London's Metropolitan Police Service for dealing with suspected suicide bombers, most notably firing shots to the head without warning, informally referred to as the Met, is the territorial police force responsible for law enforcement in Greater London, excluding the "square mile" of the City of London, which is the responsibility of which organization?

Context paragraphs:
Royal Barbados Police Force: The Royal Barbados Police Force (RBPF), as established under the Police Act, of 1961(a), and the Constitution of Barbados is a part of the government responsible for local law enforcement.  Assistant Commissioner of Police Tyrone Griffith has been acting as Commissioner of the Police since June 2013 when Commissioner Darwin Dottin was asked to retire in the public's interest.  The RBPF is divided into three territorial divisions, the Operations Support Division, the Administrative Support Division and the Criminal Investigations Division.  The organisation structure of the RBPF is modelled after London's Metropolitan Police Service.

Operation Kratos: Operation Kratos referred to tactics developed by London's Metropolitan Police Service for dealing with suspected suicide bombers, most notably firing shots to the head without warning.  The tactics were developed shortly after the 11 September 2001 attacks, based in part on consultation with Israeli and Sri Lankan law enforcement agencies on how to deal with suicide bombers.  Little was revealed about these tactics until after the mistaken shooting of Jean Charles de Menezes on 22 July 2005, in the wake of the 7 July 2005 London bombings.  The term is no longer used by the Metropolitan Police, although similar tactics remain in force.

Scotland Yard: Scotland Yard (officially New Scotland Yard) is a metonym for the headquarters of the Metropolitan Police Service (MPS), the territorial police force responsible for policing most of London.

Warwickshire Police: Warwickshire Police is the territorial police force responsible for policing Warwickshire in England.  It was known as Warwickshire Constabulary until 2001.  It is the second smallest territorial police force in England and Wales after the City of London Police, with only 998.6 (full-time equivalents) regular officers as of December 2006.  The resident population of the force area is 552,000.

Metropolitan Police Authority: 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.

Metropolitan Police District: 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.

Metropolitan Police Service: The Metropolitan Police Service (MPS), formerly and still commonly known as the Metropolitan Police, formally called the Metropolitan Police Force, and informally referred to as the Met, is the territorial police force responsible for law enforcement in Greater London, excluding the "square mile" of the City of London, which is the responsibility of the City of London Police.

Firearms unit: A firearms unit is an armed unit within each territorial police force in the United Kingdom.  For the most part, the police forces of the United Kingdom are unarmed; however, all have firearms units to provide the police force with the capability to deal with terrorists and armed criminals.  A police officer cannot apply to join the firearms unit without first finishing their two-year probationary period, with a further two years in a core policing role.  Firearms unit is the most common name outside of the capital, while that of London's Metropolitan Police Service is called the Specialist Firearms Command, or SCO19.  Within the media it is sometimes compared to the SWAT units of the United States.

Greater Manchester Police: Greater Manchester Police (GMP) is the Police Force responsible for law enforcement within the metropolitan county of Greater Manchester in North West England.  GMP is the fourth largest police service in the United Kingdom after the Metropolitan Police Service, West Midlands Police and Police Scotland; and is also the third largest of the English police forces.

City of London Police: The City of London Police is the territorial police force responsible for law enforcement within the City of London, including the Middle and Inner Temples.  The force responsible for law enforcement within the remainder of Greater London, outside of the City, is the Metropolitan Police Service, a separate organisation.  The City of London, which is now primarily a financial business district with a small resident population but a large commuting workforce, is the historic core of London, and has an administrative history distinct from that of the rest of the metropolis, of which its separate police force is one manifestation.

Supporting paragraphs: Operation Kratos Metropolitan Police Service
Answer: City of London Police