With Britain under threat of a French invasion, and most units of the British Army serving in India following the Indian Mutiny, the Volunteers were formed, a forerunner of today's Territorial Army. A number of Volunteer units formed Cadet Companies.
Queen Victoria carried out a review of the Volunteers. One unit, the Queen's Westminster's, paraded their cadets.
Schools had also started to form units and at least eight were in existence by this time.
Social reformer, Octavia Hill, formed London's first independent Cadet Battalion - the Southwark Cadet Company - in 1889. Octavia Hill felt strongly that the military context would socialise urban youths struggling for direction, and wrote that: "There is no organisation which I have found that influences the boys so powerfully for good as that of our cadets ... and if such ideals can be brought before the young lad before he gets in with a gang of loafers it may make all the difference to his life".
The title Cadet Force was introduced. The Volunteers became the Territorial Army and administration of the Cadet Force was taken over by the Territorial Army Associations.
There was a massive expansion of the Cadet Force. The War Office took over the administration of the organisation.
The government withdrew financial support for the Cadet Force and control and administration reverted to the Territorial Army Associations.
The British National Cadet Association (BNCA) was formed in an attempt to ensure the survival of the Cadet Force and to win back government support.
The BNCA was permitted to run the Cadet Force under the guidance of the Territorial Army.
The Second World War saw another big expansion of both Army Cadets and Sea Cadets and the creation of the Air Training Corps.
The War office re-assumed the administration of the Cadet Force and the title Army Cadet Force was introduced. An estimated 100,000 Army Cadets attended camp for one week that summer.
The BNCA changed its name to the Army Cadet Force Association (ACFA). A registered charity, the ACFA plays a vital role in the life of the ACF to this day.
100 school-based units left the ACF in order to join the newly-organised Combined Cadet Force (CCF).
With the War over and national service coming to an end, the government set up the Amery Committee to report on the future organisation and training of cadets. Citizenship training was one of the needs identified.
The ACF participated in a pilot scheme for The Duke of Edinburgh's Award and remains one of the UK's largest operating authorities of DofE today.
The Amery Report was published. Its recommendations continue to provide the basis of cadet training to this day.
The Cadet Training Centre at Frimley Park was established as a result of the Amery Report.
The ACF celebrated its 100th anniversary with a review of the ACF and CCF in the grounds of Buckingham Palace by Her Majesty The Queen and His Royal Highness The Duke of Edinburgh. The Duke of Edinburgh also presented a banner to the Cadet Force.
Girls were formally enrolled into the ACF following pilot schemes by a number of counties over many years. Today around 30% of Army Cadets are girls.
The cadet movement celebrated its 150th anniversary with over 150 events in communities up and down the country - and beyond - under the banner of Cadet150. The main ceremonial event took place on 6 July when over 1,700 cadets and adult volunteers paraded down the Mall for inspection by His Royal Highness The Prince of Wales before joining friends and family and VIP guests for a garden party in the grounds of Buckingham Palace. Please watch our video (above).
The ACF is one of the UK's oldest, largest and most successful youth organisations. It has a long and proud history of preparing youngsters for all walks of life and encouraging an active involvement in local communities.