Deputy assistant commissioner (DAC) is a rank in London

London

London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

's Metropolitan Police Service

Metropolitan Police Service

The Metropolitan Police Service is the territorial police force responsible for Greater London, excluding the "square mile" of the City of London which is the responsibility of the City of London Police...

 between assistant commissioner

Assistant Commissioner of Police of the Metropolis

Assistant Commissioner of Police of the Metropolis, usually just Assistant Commissioner , is the third highest rank in London's Metropolitan Police, ranking below Deputy Commissioner and above Deputy Assistant Commissioner. There are usually four officers in the rank...

 and commander. It is equivalent to deputy chief constable

Deputy Chief Constable

Deputy chief constable is the second highest rank in all territorial police forces in the United Kingdom , as well as the British Transport Police, Ministry of Defence Police and Civil Nuclear...

 in other British

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 police

Police

The police is a personification of the state designated to put in practice the enforced law, protect property and reduce civil disorder in civilian matters. Their powers include the legitimized use of force...

 forces and wears the same insignia: a pip above crossed tipstaves

Tipstaff

The Tipstaff is an officer of a court or, in some countries, a law clerk to a judge. The duties of the position vary from country to country.-History:...

 within a wreath.

The rank was introduced in 1919 as an intermediate rank between assistant commissioner and (the Metropolitan Police rank of) chief constable. Deputy assistant commissioners were always warranted constable

Constable

A constable is a person holding a particular office, most commonly in law enforcement. The office of constable can vary significantly in different jurisdictions.-Etymology:...

s, as opposed to the higher ranks who were instead sworn as magistrate

Magistrate

A magistrate is an officer of the state; in modern usage the term usually refers to a judge or prosecutor. This was not always the case; in ancient Rome, a magistratus was one of the highest government officers and possessed both judicial and executive powers. Today, in common law systems, a...

s. In 1946 the rank was split, with senior DACs continuing to hold the rank and junior DACs (the four district commanders and the deputy to the assistant commissioner "C" in the Criminal Investigation Department

Criminal Investigation Department

The Crime Investigation Department is the branch of all Territorial police forces within the British Police and many other Commonwealth police forces, to which plain clothes detectives belong. It is thus distinct from the Uniformed Branch and the Special Branch.The Metropolitan Police Service CID,...

) being regraded to the new rank of commander. On 1 April 1995, as a result of the Sheehy Report, the rank was abolished along with chief superintendent

Chief Superintendent

Chief superintendent is a senior rank in police forces organised on the British model.- United Kingdom :In the British police, a chief superintendent is senior to a superintendent and junior to an assistant chief constable .The highest rank below Chief Officer level, chief...

 and deputy chief constable, but all three ranks were reintroduced on 1 January 2002. Senior commanders were in the meantime sometimes given the designation deputy to assistant commissioner, and officers who already held the rank of DAC retained it.

All the deputy assistant commissioners initially held senior staff jobs at Scotland Yard

Scotland Yard

Scotland Yard is a metonym for the headquarters of the Metropolitan Police Service of London, UK. It derives from the location of the original Metropolitan Police headquarters at 4 Whitehall Place, which had a rear entrance on a street called Great Scotland Yard. The Scotland Yard entrance became...

. In 1933, command of the four Districts, formerly held by chief constables, was given to deputy assistant commissioners, with the chief constables remaining as their deputies. District commanders were regraded to commander in 1946, but later regained DAC rank, holding it until 1995, by which time there were eight areas (as the districts had been renamed). These were reorganised into five and handed over to the assistant commissioners.