In 2025, there were around 137,000 regular personnel serving in the British Armed Forces, compared with 138,000 in the previous year. In the first half of the twentieth century, there were two huge spikes in the number of active personnel which represented the final years of World War One and World War Two, numbering 4.58 million and 4.69 million in 1918 and 1945 respectively. Ever since 1945, the size of the regular armed forces has been in almost constant decline, with the noticeable exception of the early 1950s, when the number of active personnel increased by almost 200,000 because of the Korean War. The winds of change There are several reasons why the number of personnel in Britain’s armed forces has declined. Britain is involved in a far fewer conventional military conflicts today than it was in the past. As the size of Britain’s empire declined rapidly after 1945, so too did the UK's global military commitments. There are also more recent developments, such as the UK government’s Strategic Defence and Security Review of 2010, which outlined personnel would be cut throughout the 2010s to modernize the UK’s armed forces. Recent geopolitical events such as the War in Ukraine have, however, led to commitments from the UK government to spend more on defence, and eventually even a reversal of personnel cuts. Branches of the UK military There are three main branches of the UK armed forces, the British Army, the Royal Navy, the Royal Air Force, and the Royal Marines. Of the 181,000 people serving in the UK’s armed forces in 2025, over half of them were in the British Army, which had around 109,000 personnel. The next largest branch was the Royal Navy at 37,900, followed by the RAF at 34,800 personnel. The average age for people serving in the armed forces was 31 in 2024, with the Royal Air Force having a slightly higher average age group than the other branches, at 33.

In 2024, there were approximately 121,900 men in the armed forces of the United Kingdom, and 16,220 women. The reduction in personnel witnessed by the British Armed Forces in recent years is the result of a conscious attempt by the UK government to cut costs and modernize the military. This policy has been pursued since the 2010 Strategic Defence and Security Review, which among other things sought to replace many full-time regulars with reservists, and to end the UK’s permanent deployment in Germany. Cuts across air land and sea While the army has born the brunt of these cuts to personnel, all branches of the armed forces have also had to contend with the same issue. Since 2012, the Army has seen its personnel reduced by around 28,800, the RAF by 9,200, and the Navy by around 3,540 While the share of GDP spent on defense has not fallen quite as dramatically since 2012, over the long term, the UK has almost halved defense spending since the end of the Cold War. As of 2021, the UK spent 2.3 percent of GDP on defense, slightly above the minimum NATO requirement of two percent of GDP. Recent geopolitical events, such as the Russian invasion of Ukraine, have led to renewed calls for increased defence spending, with the current UK government aiming to spend 2.5 percent of GDP in the near future. Age of personnel In 2024, the average age across all ranks and branches in the UK armed forces was 31. This was the average age for all branches of the armed forces, except for the RAF, which had an average age of 33. During the same year, there were approximately 54,800 people in their 20s in the armed forces, compared with 45,410 in their 30s. Additionally, there were only around 7,760 people under the age of 20 in the armed forces, and just 90 aged 60 or over.

In April 2024, 13.1% of people in non-officer roles in the armed forces were from ethnic minorities, compared with 7.9% in April 2012.

In 2025, there were approximately 181,000 personnel in the armed forces of the United Kingdom, 109,170 of which were in the British Army, 37,900 in the Royal Navy and 34,830 in the Royal Air Force. Regular personnel at historical lows in 2025 Overall, there has been a long-term decline in the size of the armed forces, with the number of personnel declining from over 200,000 in 2000, to around 137,000 by 2025. In fact, the size of the armed forces has been in almost constant decline since the end of the Second World War. Britain's retreat from its colonial empire throughout this period removed many of the UK's overseas commitments, with the end of the Cold War also leading to further cuts to personnel. This has also corresponded with cuts in defence spending, which fell from 4.6 percent of GDP in the mid-1980s, to just 1.8 percent in the late 2010s Operational deaths since the Second World War Since 1945, there have been 7,193 operational deaths in the United Kingdom’s armed forces, with the deadliest year occurring in 1951 when there were 851 deaths. This was due to three separate conflicts: the Malayan Emergency, the 1951 Anglo-Egyptian War and the Korean War. Since 1959, there were only three years that had more than 100 operational deaths: 1972, 1973 and 1982. By comparison, between 2016 and 2024, there have been only nine operational deaths, with just one death reported since 2023.

Historical chart and dataset showing U.K. military size by year from 1985 to 2020.

In 2025, there were approximately ****** regular personnel in the British Armed Forces aged between 18 and 29, compared with ****** aged between 30 and 49, and ****** aged 50 and over.

United Kingdom UK: Armed Forces Personnel: % of Total Labour Force data was reported at 0.446 % in 2016. This records a decrease from the previous number of 0.456 % for 2015. United Kingdom UK: Armed Forces Personnel: % of Total Labour Force data is updated yearly, averaging 0.711 % from Dec 1990 (Median) to 2016, with 27 observations. The data reached an all-time high of 1.061 % in 1990 and a record low of 0.446 % in 2016. United Kingdom UK: Armed Forces Personnel: % of Total Labour Force data remains active status in CEIC and is reported by World Bank. The data is categorized under Global Database’s United Kingdom – Table UK.World Bank.WDI: Defense and Official Development Assistance. Armed forces personnel are active duty military personnel, including paramilitary forces if the training, organization, equipment, and control suggest they may be used to support or replace regular military forces. Labor force comprises all people who meet the International Labour Organization's definition of the economically active population.; ; International Institute for Strategic Studies, The Military Balance.; Weighted average; Data for some countries are based on partial or uncertain data or rough estimates.

This dataset provides information on where UK armed forces veterans lived: usual residents, aged 16 years and over by whether they have previously served in the UK armed forces in England and Wales.

Child family status

Identifies whether a person is living in a family with a child and has specific categories for those who have children based on the relationship of the parent couple, those not in a family and those who are children in a family are grouped together. Categories were: • has children (in a lone parent family, married couple family, civil partnership family or cohabiting couple family) • does not have children or is a child within a family • living in a communal establishment

Dependent Child

A dependent child is a person aged 0 to 15 years in a household or a person aged 16 to 18 years who is in full-time education and lives in a family with their parent, parents, grandparent or grandparents. It does not include any person aged 16 to 18 years who has a spouse, partner or child living in the household

Ethnic group and high-level ethnic group

The ethnic group that the person completing the census feels they belong to. This could be based on their culture, family background, identity or physical appearance. Respondents could choose one out of 19 tick-box response categories, including write-in response options. High-level ethnic group refers to the first stage of the two-stage ethnic group question. High-level groups refer to the first stage where the respondent identifies through one of the following options: "Asian, Asian British, Asian Welsh" "Black, Black British, Black Welsh, Caribbean or African" "Mixed or Multiple" "White" "Other ethnic group"

Family

A family is a group of people who are either: • married, civil partnered or cohabiting couple with or without children (the children do not need to belong to both members of the couple) • a lone parent with children • a married, civil partnered or cohabiting couple with grandchildren but where the parents of those grandchildren are not present • a single or couple grandparent with grandchildren but where the parents of those grandchildren are not present

Family status

Denotes whether a person is considered to be in a family and the place a person holds within that family. Categories were: • not in a family • in a couple family (as a member of the couple or a dependent or non-dependent child of one or both members of the couple) • in a lone parent family (as a parent or a dependent or non-dependent child of the parent) • living in a communal establishment

Household

A household is defined as one person living alone or a group of people (not necessarily related) living at the same address who share cooking facilities and a living room or dining area. This includes all sheltered accommodation units in an establishment and all people living in caravans on any type of site that is their usual residence. A household must contain at least one person whose place of usual residence is at the address. A group of short-term residents living together is not classified as a household, and neither is a group of people at an address where only visitors are staying.

Household size

The number of people in the household. Visitors staying at an address do not count to that household’s size. Living arrangements This classification combines responses to the Census question on marital and civil partnership status with information about whether or not a person is living in a couple. This topic is only applicable to people in households. Living arrangements differs from marital and civil partnership status because cohabiting takes priority over other categories. For example, if a person is divorced and cohabiting, then in results for living arrangements they are classified as cohabiting.

UK armed forces veteran

People who have previously served in the UK armed forces. This includes those who have served for at least one day in HM’s Armed Forces, either regular or reserves, or Merchant Mariners who have seen duty on legally defined military operations. It does not include those who have left and since re-entered the regular or reserve UK armed forces, those who have only served in foreign armed forces, or those who have served in the UK armed forces and are currently living outside of England and Wales.

Usual resident

A usual resident is anyone who on Census Day, 21 March 2021, was in the UK and had stayed or intended to stay in the UK for a period of 12 months or more, or had a permanent UK address and was outside the UK and intended to be outside the UK for less than 12 months.

In 2025, there were around ******* service personnel in the United Kingdom's Ministry of Defence, compared with ******* in 2012.

This dataset is an analysis of the Characteristics by previous service as a regular or reserve in the UK armed forces from Census 2021.

People who have previously served in the UK armed forces includes those who have served for at least one day in HM’s Armed Forces, either regular or reserves, or Merchant Mariners who have seen duty on legally defined military operations. It does not include those who have left and since re-entered the regular or reserve UK armed forces, those who have only served in.

Country of birth

The country in which a person was born. For people not born in one of in the four parts of the UK, there was an option to select "elsewhere". People who selected "elsewhere" were asked to write in the current name for their country of birth.

Ethnic group and high-level ethnic group

The ethnic group that the person completing the census feels they belong to. This could be based on their culture, family background, identity or physical appearance. Respondents could choose one out of 19 tick-box response categories, including write-in response options. High-level ethnic group refers to the first stage of the two-stage ethnic group question. High-level groups refer to the first stage where the respondent identifies through one of the following options: * "Asian, Asian British, Asian Welsh" * "Black, Black British, Black Welsh, Caribbean or African" * "Mixed or Multiple" * "White" * "Other ethnic group"

General health

A person's assessment of the general state of their health from very good to very bad. This assessment is not based on a person's health over any specified period of time.

Legal partnership status

Classifies a person according to their legal marital or registered civil partnership status on Census Day 21 March 2021.

Religion

The religion people connect or identify with (their religious affiliation), whether or not they practice or have belief in it. This question was voluntary, and the variable includes people who answered the question, including “No religion”, alongside those who chose not to answer this question. This variable classifies responses into the eight tick-box response options. Write-in responses are classified by their "parent" religious affiliation, including “No religion”, where applicable.

Usual resident

A usual resident is anyone who on Census Day, 21 March 2021, was in the UK and had stayed or intended to stay in the UK for a period of 12 months or more, or had a permanent UK address and was outside the UK and intended to be outside the UK for less than 12 months.

UK armed forces veteran

People who have previously served in the UK armed forces. This includes those who have served for at least one day in HM’s Armed Forces, either regular or reserves, or Merchant Mariners who have seen duty on legally defined military operations. It does not include those who have left and since re-entered the regular or reserve UK armed forces, those who have only served in foreign armed forces, or those who have served in the UK armed forces and are currently living outside of England and Wales.

In 2024, there were no operational deaths in the British Armed Forces, compared with one in 2023. Since 1945, the deadliest year for British Armed Forces was 1951 when there were 851 operational deaths. This was due to three separate conflicts: the Malayan Emergency, the 1951 Anglo-Egyptian War and the Korean War. Between 1959 and 2009 there were only three years that had more than 100 operational deaths: 1972, 1973 and 1982. The spike in deaths in the early 1970s were the result of the political violence in Northern Ireland at the time, and 237 of the 297 deaths in 1982 happened during the Falklands War. Over this period, there have been a total of 7,193 British military deaths in conflicts. Size of armed forces at a historic low in 2024 The British Armed Forces are composed of three main separate branches, the British Army, the Royal Navy, and the Royal Air Force. Of these branches, the British Army has more personnel than the other two combined at around 75,300. The Royal Navy and Marines had 32,000 personnel, while the Royal Air Force had 30,800 active personnel. This was the fewest number of personnel in modern times, and is partly explained by previous modernization efforts, which sought to de-emphasize the importance of a large army based on manpower in favor of a more advanced one based on technology. Long-term defense cuts   These cutbacks in personnel are also a result of the UK government spending far less on defense than it used to. In 1984, for example, the UK spent around 5.5 percent of GDP on defense, compared with just 2.3 percent in 2021. The end of the Cold War in the early 1990s made it difficult to justify 1980s-levels of military spending during this time period, along with the UK having far fewer overseas commitments than in the past. Russia's full-scale invasion of Ukraine in 2022, however, looks set to reverse this trend, with many NATO allies pledging to increase their defense budgets in light of the new geopolitical situation.

This dataset provides Census 2021 estimates that classify households in England and Wales by the number of people in the household who have previously served in the UK armed forces. The estimates are as at Census Day, 21 March 2021.

This does not include people who are currently serving in the UK armed forces.

Many who have previously served in the UK armed forces will be older males because of National Service. We applied extra quality assurance to correct some answers from currently serving personnel.

Read more about this quality notice.

Area type

Census 2021 statistics are published for a number of different geographies. These can be large, for example the whole of England, or small, for example an output area (OA), the lowest level of geography for which statistics are produced.

For higher levels of geography, more detailed statistics can be produced. When a lower level of geography is used, such as output areas (which have a minimum of 100 persons), the statistics produced have less detail. This is to protect the confidentiality of people and ensure that individuals or their characteristics cannot be identified.

Lower Tier Local Authorities

Lower tier local authorities provide a range of local services. In England there are 309 lower tier local authorities. These are made up of non-metropolitan districts (181), unitary authorities (59), metropolitan districts (36) and London boroughs (33, including City of London). In Wales there are 22 local authorities made up of 22 unitary authorities. Of these local authority types, only non-metropolitan districts are not additionally classified as upper tier local authorities.

UK armed forces veteran indicator

Identifies people who have previously served in the UK armed forces. This includes those who have served for at least one day in armed forces, either regular or reserves, or Merchant Mariners who have seen duty on legally defined military operations.

In 2025, the average age for personnel in the UK Armed Forces overall was 31 years old. The average age of those serving in the British Army was also 31, with the average age rising to 33 for the Royal Air Force (RAF). The average age for officers in the Armed Forces was 37, with this rising to 38 for officers in the Royal Air Force.

In 2024, people aged between 25 and 29 were the most common age group in the armed forces of the United Kingdom, at 27,580 personnel. By contrast, there were just 100 active personnel that were aged sixty or over.

A substantial amount of research has been conducted into the mental health of the UK military in recent years. This article summarises the results of the various studies and offers possible explanations for differences in findings between the UK and other allied nations. Post-traumatic stress disorder (PTSD) rates are perhaps surprisingly low amongst British forces, with prevalence rates of around 4% in personnel who have deployed, rising to 6% in combat troops, despite the high tempo of operations in recent years. The rates in personnel currently on operations are consistently lower than these. Explanations for the lower PTSD prevalence in British troops include variations in combat exposures, demographic differences, higher leader to enlisted soldier ratios, shorter operational tour lengths and differences in access to long-term health care between countries. Delayed-onset PTSD was recently found to be more common than previously supposed, accounting for nearly half of all PTSD cases; however, many of these had sub-syndromal PTSD predating the onset of the full disorder. Rates of common mental health disorders in UK troops are similar or higher to those of the general population, and overall operational deployments are not associated with an increase in mental health problems in UK regular forces. However, there does appear to be a correlation between both deployment and increased alcohol misuse and post-deployment violence in combat troops. Unlike for regular forces, there is an overall association between deployment and mental health problems in Reservists. There have been growing concerns regarding mild traumatic brain injury, though this appears to be low in British troops with an overall prevalence of 4.4% in comparison with 15% in the US military. The current strategies for detection and treatment of mental health problems in British forces are also described. The stance of the UK military is that psychological welfare of troops is primarily a chain of command responsibility, aided by medical advice when necessary, and to this end uses third location decompression, stress briefings, and Trauma Risk Management approaches. Outpatient treatment is provided by Field Mental Health Teams and military Departments of Community Mental Health, whilst inpatient care is given in specific NHS hospitals.

After the Second World War, the deadliest conflict for the British Armed Forces was the Malayan Emergency, which lasted from 1948 to 1960 and resulted in the deaths of 1,442 British soldiers. Over a much longer time period, between 1968 and 2007, there were 1,441 operational deaths for the British Armed Forces in Northern Ireland. The Korean War was a noticeably deadly conflict despite its relatively short duration, and had the third-highest number of fatalities for British troops at 1,129. The wars of decolonization The rapid disintegration of the British Empire after 1945 is the cause of many of the conflicts displayed here. In the aftermath of World War Two, there were 70 modern-day countries in the British Empire, but by 1997, Britain’s colonial Empire had vanished. The Palestinian Emergency, which after 1945 caused 754,000 British casualties, as well as the aforementioned Malayan Emergency are just some examples of Britain’s disorderly withdrawal from regions it once controlled. Although the UK won the Falklands War in 1982, the UK's armed forces suffered 237 operational deaths in the ten-day conflict. Recent conflicts The UK armed forces have been involved in several more recent military conflicts, and the deadliest of these was by far the War in Afghanistan, which was responsible for 457 British fatalities. The UK’s involvement in the fight against ISIS in Iraq and Syria is also ongoing, although unlike the Iraq War that took place between 2003 and 2011, where the UK suffered 178 operational deaths, the conflict is fought primarily by the air force. Although no UK soldiers are fighting the War in Ukraine, the UK government has provided extensive equipment and training to the Ukrainian armed forces since 2022, along with several other western nations.