The NAO roots trace back to the national festival which began holding the Accordion Day annual competitions in 1935, the first event being at the Westminster Central Hall, London. There was a forced hiatus during the war years from 1938 - 1948, however the Accordion Day competitions resumed again in 1949.

As this great revival in the interest of music making gathered impetus and more and more accordionists rallied together, the NAO gradually took shape under the provisional leadership of Messrs. Black, Bridger and Meyer. They were soon joined by many others who wished to see a powerful association for accordionists founded on a sound and democratic basis.

In 1949, the first formal meeting of The National Accordion Organisation of Great Britain was held, the original Memorandum of Constitution was confirmed, rules were formulated and adopted, and officers and committee elected. Mr. Toralf Tollefsen was elected the first President, and Gerald Crossman the first Vice-President. Dr. Otto Meyer was elected Chairman, Mr. H. J. Bridger the Treasurer, and Mr. Jimmy Black the Hon. General Secretary. From the outset, provision was made for a specialist section for teachers, and Mr. Graham Romani was elected Organiser of the Accordion Teachers' Guild.

The NAO is a truly national organisation which caters always for the main body of British accordionists and numbers almost every well-known name in the accordion world among its members. In January 1950, the the NAO was officially admitted as a founder member of the Third Constitutive Assembly of the Confederation Internationale des Accordeonistes (CIA) and it therefore follows that those who join the NAO also become members of this international brotherhood of accordion players.

The newly formed NAO continued holding its annual festival in London until 1963. From 1964 to 1970, the event was held in Leicester under the direction of Francis Wright and from 1971 to 1992, the UK Accordion Championships were held in various locations including: Southampton (1971), Perth (1973), Brighton (1974), Margate (1978), Troon (1981), Buxton (1984), Blackpool (1987).The United Kingdom Accordion Championships are now held annually at the beautiful seaside resort of Scarborough.

In 1987 the NAO changed its name to become The National Accordion Organisation of the United Kingdom to include competitors from Northern Ireland.

The founding President, the late Toralf Tollefsen, was born in Glemmen, Norway. He began playing the accordion at the age of 5, and by 15 years of age, was entertaining at local restaurants. Within two or three years, he was engaged as an entertainer on the cruise lines, which ultimately brought him to England in 1935. Tollefsen made contact with Recording Companies and was offered work with the BBC and soon became a household name throughout England. He married in 1938 but during the War, his permit ran out and he had to return to Norway. As soon as the war was over, he returned to England for a series of very successful concerts at Royal Albert Hall and a tour to the United States. It was during this return to England that Tollefsen became the NAO President. Tollefsen returned to Norway with his wife and daughter in 1961, but continued to hold the title of the NAO President until his death.

In 2001, Jack Emblow was appointed the Third Honorary NAO President in honor of his contribution to the accordion in the UK.

The NAO has hosted the prestigious Coupe Mondiale World Accordion Championships for the CIA five times. These were held in Brighton - 1955, Leicester - 1968, Folkstone - 1984 London - 2001 and most recently Glasgow -2008.

Currently, the NAO Executive Committee continues to make many advancements and the UK Championships is currently experiencing great times. It has never been in a position to welcome so many international stars to its prestigious event. With again, over 400 entries in 2009 in the various classes, the competition has really established itself as the premiere accordion festival in the UK.