People and Organisation

People and Organisation

Introduction to People and Organisation


MI5 currently employs more than 5,000 people. 

At any time, several hundred staff may work in MI5 on secondment or attachment from other government departments and agencies.

Staff roles cover a number of areas including investigations, translation, data analysis, technology, surveillance, communications, information management, protective security, administration, building services and catering.

MI5’s headquarters are at Thames House, a Grade II listed building situated only a few hundred yards from the Houses of Parliament in London. We also have several regional offices and a headquarters in Northern Ireland.


MI5 operates under the statutory authority of the Home Secretary, but it is not part of the Home Office .

The head of MI5 is the Director General (DG), currently Ken McCallum. He is supported by the Deputy Director General (DDG), Director General Capability (DGC), Director General Strategy (DGS) and Director General Corporate Services (DGCS).

The Deputy and Assistant Directors General share responsibility for MI5’s capabilities and functions, which are organised across ten branches.

The National Protective Security Authority (NPSA) is part of MI5 and provides advice on physical and personnel security to help organisations put measures in place to reduce their vulnerability to terrorism and state threats.

The Joint Terrorism Analysis Centre (JTAC) is also accountable to the Director General, although is a self-standing organisations staffed by representatives from multiple government departments.



MI5's budget is paid from the Single Intelligence Account (SIA) which also provides funding for the Secret Intelligence Service (SIS) and Government Communications Headquarters (GCHQ).

The SIA's budget is decided by Ministers through the Spending Review. This process helps Ministers decide how much to spend on security and intelligence, in line with decisions on overall government spending.

The SIA was provided a settlement of £2.4bn in 2018-19. The agencies are also able to bid for additional resources from the Joint Security Fund, which is shared with the Foreign Office, Ministry of Defence and Departments for International Development. The breakdowns for the individual agencies are not published for security reasons.

How we allocate resources

At any one time the UK faces a range of covert threats to its security and MI5 has only finite resources with which to counter them. We prioritise the threats and allocate resources accordingly, taking into account the national intelligence priorities set by the Joint Intelligence Committee (JIC) .While we don't publish MI5's share of the SIA budget, the diagram below gives an overview of how we use our resources.

Allocation of resources by core business, 2018/19:

  • 67% international counter-terrorism
  • 20% Northern Ireland-related terrorism
  • 13% counter-espionage, counter-proliferation and protective security

Financial oversight

We are subject to close budgetary scrutiny and challenging efficiency targets. Although we have to operate in secret, we have to account for the money we spend in the same way as other public sector organisations and our accounts are audited by the National Audit Office (NAO). NAO staff have access to relevant MI5 records for this purpose. In addition, our expenditure and resource allocations are scrutinised by the Intelligence and Security Committee (ISC). The ISC's annual reports provide further details of the agencies' funding and expenditure..

Royal Patronage

In 2011, His Royal Highness The Prince of Wales agreed to become Royal Patron of the Intelligence Services (MI5, SIS and GCHQ).

Cinquefoil Trust

The Cinquefoil Trust is a registered charity established to support current and former members of MI5, and their dependents and those in a family relationship with them, who find themselves in challenging circumstances. If you are in need of support and think you may be eligible for the Trust’s help, please contact us at the address below. Our charitable objects in full are:

  • the provision of grants to registered charities; and
  • the promotion of the efficiency of the Security Service (MI5) through the relief of need (by reason of health, disability, age, financial hardship or disadvantage) amongst serving and former members, their dependants and those in a family relationship with such members and former members, and through provision of support and assistance to enhance their morale and well-being.

In fulfilling these objectives, the Trustees generally use the following definitions:

A ‘dependant’ is taken to mean an individual who requires financial support from a serving or former member. Emotional or other forms of dependence will not qualify. The financial dependence must be substantial and continuing. It is insufficient, therefore, that an individual occasionally requires financial support from a serving or former member, or that they require continuing financial support that is not substantial. Whether support is substantial will depend on all the circumstances of the case.

A ‘family relationship’ is taken to mean an individual will be regarded as in a family relationship with a serving or former member if (a) they are married to, in a civil partnership with or cohabiting with that member, or are related to that member by blood or adoption, or are the member’s step child, step parent, step sibling, ward, or foster child, and (b) they are resident in the member’s household. An individual will be regarded as in a family relationship with a deceased former member if conditions 1(a) and (b) were satisfied at the time of the former member’s death.’ • The Trust may make exceptions to the above in exceptional circumstances and only where the Trustees consider the merits of the case to be compelling. All staff and former staff, and their dependants and those in a family relationship with them, are eligible to apply for assistance, irrespective of length of service or grade.

The Cinquefoil Trust is here to provide support to all our beneficiaries when they need it, whatever the cause. Changes in personal financial circumstances, or in health or well-being, can affect any of us, at any time, through no fault of our own. We may be able to help with more than you might think. If you wish to apply for support, or just to see whether we may be able to help you, please get in touch at Cinquefoil Trust, PO Box 3255, London SW1P 1AE.

The Cinquefoil Trust is registered charity no. 1182006. As a registered charity, the Trust is independent of MI5 but works closely with MI5 where this facilitates the discharge of our charitable objects.

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