When police agencies work together, is one of them in charge?

Offences cross the boundaries that jurisdiction draws, so systems need some way for separate forces to act coherently. What they mostly build is coordination, because the alternative — giving one force authority over the others — would undo the reason the forces were separated in the first place.

AnalysisThe result is a set of arrangements that produce cooperation without concentrating authority: shared standards, shared information, mutual assistance, and temporary command structures created for a specific operation and dissolved afterwards.

Standard-setting

A national body defines training, procedure or equipment standards that separate forces adopt. Influence over how policing is done, without authority over any particular decision.

Information sharing

Access to records and intelligence. Frequently the most consequential form of cooperation, and it confers no command at all.

Mutual assistance

One force supports another on request. The requesting force normally retains responsibility for the operation.

Joint operations

A temporary command structure created for a specific operation, under which officers of several forces work. It ends with the operation; the underlying legal authority of each force is unchanged.

Supervision

A body reviewing another’s conduct after the fact. Distinct from command, which is contemporaneous and directive.

Japan is the clearest worked example of coordination that is not command: the National Public Safety Commission supervises the National Police Agency, which together constitute the national police organisation, while policing itself is administered at prefectural level.

Switzerland states the negative directly. The country has no national police force, each canton is responsible for policing its own territory under its own police law, and the federal office of police is not a superordinate authority but works alongside those forces.

• Common belief: If a national agency assists a local force, it has taken over the case.

  In practice: Assistance is normally provided on request, with the requesting force retaining responsibility. Which body leads is settled by law and protocol, not by which is larger.

• Common belief: National standards mean national command.

  In practice: A body can set training and procedural standards for forces it has no authority to direct. Japan’s national organisation coordinates and supervises while prefectures administer the policing.

• Common belief: Sharing information means one agency controls the other.

  In practice: Information sharing is the most common form of cooperation and confers no authority whatsoever over another force’s decisions.

• Common belief: A federal police force is the boss of local police.

  In practice: In most systems it holds different jurisdiction rather than superior authority — and in Switzerland the federal office says in terms that it is not superordinate.

• Some systems place a national body with genuine directive powers over sub-national forces; most do not, and the difference must be established rather than assumed.
• Where a prosecutor or investigating judge directs investigations, a form of command exists that is judicial rather than police.
• Joint operation arrangements differ in whether a single commander is appointed and what happens to officers’ home-force powers while seconded.
• A unitary state with one national force may have genuine hierarchical command throughout, which is a different situation from any of the above.

Australia illustrates a federal force whose own authority is statutory and bounded rather than supervisory over the state forces.

Japan

The National Public Safety Commission and the National Police Agency form the national police organisation, the Commission supervising the Agency, while operational policing is administered by the prefectures. National coordination and standard-setting, exercised through a civilian commission, is not the same thing as commanding each operational act.

Switzerland

The federal office of police states plainly that it is not a superordinate authority but works alongside the cantonal forces, each canton policing its own territory under its own police law. Cooperation between peers, with no apex to appeal to.

France

France is the contrast: a national police force with a single chain of command under national authority, alongside a gendarmerie defined by statute as an armed force instituted to ensure the execution of the laws. Where a system genuinely is hierarchical, command really does run downwards — which is why hierarchy has to be established for a given system rather than assumed from the existence of a national body.

Because responsibility follows command, the question "who was in charge?" is the first thing an oversight body has to settle after a joint operation — and it is frequently contested precisely because coordination leaves each force answerable for its own part.

Related: what police jurisdiction means, police search and rescue, prefectural police, and how police are held to account. Where a single specialist unit serves a whole country by request rather than by command, see how specialist units cover a country.