Deploying the armed forces in the UK

Armed forces personnel can be deployed on operations in the UK when asked to do so by relevant civil authorities.

This may be to assist with flood relief, bomb disposal or supporting major national events like the 2012 Olympic or 2022 Commonwealth Games.

Such requests are known as Military Aid to the Civil Authorities (MACA). The armed forces do not maintain specific forces to assist civil authorities, as assistance is provided depending on the requirement. Defending the UK against military threats is distinct to MACA and is not the subject of this briefing paper.

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). Requests for military assistance must be approved by the Ministry of Defence, unless there are exception circumstances such as an urgent need to protect life.

What sort of things might the armed forces do?

Military personnel can be called upon to assist civil authorities for 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 to provide additional security for national events like the 2012 Olympic Games, the G8 or NATO Summits, or the 2022 Commonwealth Games.

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

Do soldiers carry their weapons?

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

Can soldiers arrest people?

Responsibility for law enforcement lies with the police and the Home Office. The MOD guidance is clear that all MACA operations must be conducted within the law. Unlike the police, service personnel only have the same powers of arrest as ordinary citizens.

The Ministry of Defence does have a specialist armed police force (the MDP). 

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.

Are the armed forces being used “more often”?

In a report published in July 2022, The Defence Committee observed the armed forces are being used “more and more often”, at a time when they are facing cuts to personnel numbers:

[…] We are seeing Defence being used more and more often as an emergency measure to relieve exceptional pressures on public services and perform such tasks that otherwise might be expected to be carried out by others.

In its report for 2022, the Armed Forces Pay Review Body reported personnel felt the “the armed forces had been asked to help support a government response to one event after the other”. The body talks to personnel as part of its information gathering on pay, and notes the wider sense that personnel “felt that they were continually being asked to do more with less”. The body noted the impact this can have on morale and motivation.

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 fourth edition was published in December 2021 and is the primary source for this briefing paper.