Metropolitan Police Service (overview)

The Commissioner is the overall head of the Metropolitan Police and the most senior police officer in the United Kingdom.

Assistant Commissioners have responsibility for particular aspects of policing, for example, territorial (mostly uniform), professionalism, training, operations, etc., overseeing ‘departments’. 

The precise names and responsibilities have changed over time, though they were often simply referred to by a letter for much of the Met's existence. 

However, for the majority of the period the Undercover Policing Inquiry is concerned with (1968-2011), the relevant Assistant Commissioner was known as ‘C’ Not to be confused with ‘C’ Squad within Special Branch.  and had responsibility for all detective work; this included the Criminal Investigations Department (CID) and Special Branch. Later it was renamed as Assistant Commissioner Specialist Operations (ASCO).

The Commissioner and Assistant Commissioners combined are also referred to as the ‘Chief Officers Group’. For much of the period under consideration by the Inquiry, the structure was unchanged until there was a series of re-organisations as part of modernisation drives in the late 1990s/early 2000s. It was in this period that Assistant Commissioner C became ASCO and units under him (usually) given the code prefix 'SO' - SO10 being covert policing, SO12 Special Branch, and SO13 Anti-Terrorism Branch

These same re-organisations saw the end of the Metropolitan Police Special Branch when it was merged with SO13 to form SO15 Counter Terrorism Command.

Under the Assistant Commissioners were Deputy Assistant Commissioners (DACs) who would have particular responsibilities, though, again, what these were and what they were called varied over time. Within ‘C’ department such roles included DAC (Security) which oversaw the Metropolitan Police Special Branch. Other commands with in C Division included Operations (Crime Commander), Support and Identification and Protection (including SO14, SO16 and SO17). Anti-Terrorism Branch / SO13 was included along side SO12 Special Branch in Security.

Finally, Commanders were one rank lower, considered equivalent to Assistant Chief Constables in other UK police forces. They sometimes oversaw ‘directorates’, such as Intelligence, depending on the era.

The rank of the head of the Metropolitan Police Special Branch also changed over the period of the SDS’s history. Initially it was at Chief Superintendent level but in 1969 became that of Commander. 

Confusion is sometimes caused by the word ‘commander’ being used to refer to the head of a unit rather than necessarily denoting the rank of Commander. For much of the period concerned, the head of Special Branch was at Commander rank, though it was also elevated to the rank of Deputy Assistant Commissioner for a period. This reflected its increasingly important role in counter-terrorism within UK policing; particularly when it was responsible for Irish-related matters.

More detail on this can be found in the Police and Constabulary Almanacs, which contain a wealth of detail, breaking down the various divisions and their labels, and their commanding officers.

The following were Deputy Assistant Commissioners in the line of command for Metropolitan Police Special Branch. Sometimes they were referred to as DAC (Security). The rank of Deputy Assistant Commissioner was introduced in 1969 and discontinued in 1996 in favour of the lower rank of Commander. It was reintrouced several years later as DAC (Security), but it appears that the Head of Special Branch continued at Commander level.

As well as overseeing SO12 Special Branch, DAC (Security) had responsibility for the Intelligence Directorate (SO10 & SO11) and Protection Command (SO14, SO16, SO17).