Under Barnes's leadership the academy expanded and flourished, receiving a royal charter in 1920, opening its own theatre in 1921 and, from 1923, awarding degrees under the aegis of the University of London.

[2] After leaving Oxford, Barnes became a civil servant, with an undemanding post in the Land Registry, enabling him to live in London and enjoy membership of the Garrick Club, cricket at Lord's, and West End theatre.

[5] It was intended to be a British equivalent of the Paris Conservatoire, providing what Tree described as the "elementary training which is recognised as useful in every other art and in every other profession".

He revived its fortunes by instituting rigorous procedures for auditioning applicants, maximising the income from fees, and establishing student scholarships related to performance.

[2] He acquired for the academy the house and garden adjacent to its Gower Street premises to make room for expansion and the construction of a theatre for public performances.

[2] When Barnes returned to England in December 1919 and resumed his post at the academy he found it in financial difficulties and short of students.

[2] After continual lobbying by Barnes the British government awarded the academy an annual grant from 1924 and recognised it as a charity in 1926, thus exempting it from income tax.

[4] In 1930, after prolonged legal action, Barnes won from the courts a decision that acting was henceforth to be classed as a fine art on a par with literature, painting, sculpture, architecture, and music.

The Tatler commented, "It is impossible to compute the debt which the theatre in this country owes to Sir Kenneth in his record-breaking forty-six years in Gower Street with an interlude for Army service overseas throughout World War One and for a generation the West End stage has been brilliant with the stars he has kindled".