The cultural contribution of Brian Epstein has been saluted in central London with the unveiling of a heritage plaque by Cilla Black outside the former management office of “the fifth Beatle”.

In 1963, Epstein moved his NEMS administrative operation from Liverpool to 13 Monmouth Street, in the Seven Dials area between Covent Garden and Leicester Square and worked from there until the following year.

If The Beatles “were his babies, I was the only girl,” Ms Black recalled. “He called me ‘my Cilla’ and was very protective of me. He knew everything about everything – not only rock ‘n’ roll, but classical as well. His memory was unbelievable. He had a computer for a brain.”

Epstein died in 1967 at the age of 32 and among tributes to the ceremony organisers, Cynthia Lennon wrote: “I miss him now as much as I missed him then.”

He had been “instrumental in changing all our lives with his vision, generosity and dedication. He brought culture to our gauche young lives with an experience beyond his years.”

The Beatles’ producer, Sir George Martin, recalled being swayed by Epstein’s “unwavering belief” in the band. “His energy and devotion allowed him to build an artist roster of unparalleled success.”

Epstein had diversified into West End theatre ownership and production and Ms Black believes that had he lived, he would have broadened his involvement in the arts. “Who knows? He could have been the Andrew Lloyd Webber of today.”

The unveiling was staged by the Seven Dials Trust and property firm Shaftesbury.