The Army Cadet Force began in 1859 at the time of the threat of invasion by the French. By 1860 at least 8 schools had formed Volunteer Companies for their senior boys and masters. 1860 saw the formation of Cadet Units in schools, the forerunner of today's Army Cadet Force.
Miss Octavia Hill, a Social Reformer and founder member of the National Trust, saw the benefits Cadet Units could offer the boys of London.

By the start of the Boer War about 50 schools had Cadet Corps.
The formation of the Territorial Army in 1908 promoted the expansion of school and open units of the newly named 'Cadet Force'.
In the First World War a big expansion of the Cadet Force took place and the War Office took responsibility for the organisation. Financial support was withdrawn by the Government in 1930 and, until 1942 when the Government resumed responsibility, the organisation struggled, finding its own finances. During this period the British National Cadet Force (BNCA) oversaw the running of the Cadet Force.
Another large expansion took place and by 1945 the BNCA, renamed the Army Cadet Force Association (ACFA) took sole responsibility for aspects of cadet training and activities which were not the direct concern of the MOD.
In 1957 the Cadet training Centre at Frimley Park was opened to provide courses for Officers and Adult Instructors of the Army Cadet Force (ACF) and the Combined Cadet Force (CCF). Additionally a number of leadership courses are run for Senior Cadets.
The Duke of Edinburgh celebrated the Centenary of the ACF in 1960 with the presentation of a banner. A parade in the grounds of Buckingham Palace before the Queen and the Duke of Edinburgh and a thanksgiving service in Westminster Abbey continued the celebrations.

Over the years the Cadet Force has played a part in providing the inspiration for young people to join the Services.
Cadet training, by encouraging self discipline, developing leadership qualities, giving them skills and a strong sense of community sprit, is also useful for those who enter civilian employment.

The Cadet Force today has 43 000 boys and girls aged between 12 years [in year 8 at High School] and 18 yrs 9 months in 1700 Detachments across the UK.

Octavia Hill's birthplace was Wisbech, Cambridgeshire, where a small Museum is located in the house where she was born.
Each year the Friends of Octavia Hill hold an Annual Church Service to remember her work, in which Cambridgeshire ACF play an active part.

Like many organisations, the Army Cadet Force has a Charter:

The Army Cadet Force is a National Voluntary Youth Organisation.

It is sponsored by the Army and provides challenging military, adventurous and community activities.

Its aim is to inspire Young People to achieve success in life with a sprit of service to the Queen, their Country and their local community and to develop in them the qualities required of a good citizen.

This Aim is achieved by:

1. Providing progressive Cadet Training, often of a challenging and exciting nature, to foster confidence, self reliance, initiative, loyalty and a sense of service to other people.

2. Encouraging the development of personal powers of practical leadership and the ability to work successfully as a member of a Team.

3. Stimulating an interest in the Army, it's achievements, skills and values.

4. Advising and preparing those considering a career in the Regular or Reserve Forces.