But as Sheridan Morley perceptively remarked in 2000 , when reviewing Cressida : â Gambon 's eccentricity on stage now begins to rival that of his great mentor Richardsonâ . But as Sheridan Morley perceptively remarked in 2000 , when reviewing Cressida : `` Gambon 's eccentricity on stage now begins to rival that of his great mentor Richardson '' .