House of Commons Library

Military aid to the Civil Authorities

Published Friday, August 18, 2017

When can the armed forces be deployed in the UK? This Commons Library briefing paper looks at Military Aid to the Civil Authorities

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When can the armed forces be deployed in the UK?

Civil authorities take the lead in responding to any emergencies or non-military threats to the safety and security of the UK and its citizens. Government departments or civil authorities may call upon the armed forces to assist in the planning for or response to an emergency. This is known as Military Aid to the Civil Authorities (MACA). Ministerial approval is required except when life is considered to be immediately at risk.

Defending the UK against military threats is distinct to MACA and is not the subject of this briefing paper.

What sort of things might the armed forces do?

A wide-range of tasks. But broadly speaking the military may be called upon in an emergency:

  • for their niche capabilities
  • general support when civil authorities’ capacity/capability is overwhelmed by an incident
  • in preparation for major national events

Military personnel may be called out in a wide-variety of tasks, from bomb disposal to helping with flood relief. Or for national events like the 2012 Olympic Games, G8 or NATO Summit.

Military personnel have also supported the police in response to terror threats or attacks, most recently after the attacks in Manchester in May 2017.

Defence provided support to the civil authorities on over 80 occasions in 2016-17.


What is the legal basis?

The legal authority to use Service personnel in operations under Military Aid to the Civil Authorities (MACA) is governed by the Civil Contingencies Act 2004 and the Emergency Powers Act 1964 (Section 2). In addition, service personnel can deploy under the Royal Prerogative for military tasks.

Do soldiers carry their weapons?

Very rarely. Explicit authorisation is required for personnel to be armed.

Who pays?

With a few exceptions, MACA activity is not funded from the Defence budget. As such, the Ministry of Defence can recover the costs involved, depending on the assistance required. There is no cost involved if an immediate military intervention is required to prevent the loss of life. Full costs are recovered for non-emergency, planned routine support.

Further resources:

Library briefing paper Dealing with civil contingencies: emergency planning in the UK, CBP08016, looks at emergency planning in the UK: the responsibilities of each of the responding agencies and how those fit within the framework for planning for and responding to civil contingencies laid down by Government.

Joint Doctrine Publication (JDP 02) Operations in the UK: defence contribution to resilience outlines the contribution of the armed forces to UK resilience. The third edition was published in February 2017 and is the primary source for this briefing paper.





Commons Briefing papers CBP-8074

Author: Louisa Brooke-Holland

Topics: Armed forces, Defence policy, Emergencies and disaster management, Military operations

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