One of Spinetti's most challenging theatre roles was as the principal male character in Jane Arden's radical feminist play "Vagina Rex and the Gas Oven", which played to packed houses for six weeks at the Arts Lab on Drury Lane in 1969. In 1980 he directed "The Biograph Girl", a musical about the silent film era, at the Phoenix Theatre. In 1986 he appeared as Fagin in the musical "Oliver!", which was the last professional production to use Sean Kenny's original stage design. He appeared on Broadway in "The Hostage" and "The Philanthropist", and also acted in 1995 with the Royal Shakespeare Company, in such roles as Lord Foppington in "The Relapse" and the Archbishop in "Richard III", at Stratford-upon-Avon, although this was not a happy experience for him.