In 1984, the Prince of Wales described a proposed extension to which building as a "monstrous carbuncle"?

Charles, Prince of Wales (Charles Philip Arthur George, born 14 November 1948) is the eldest child and heir apparent of Queen Elizabeth II. Known alternatively in South West England as Duke of Cornwall and in Scotland as Duke of Rothesay, The Prince of Wales has openly expressed his views on architecture and urban planning, fostering the advancement of New Classical Architecture, and asserting that he "care[s] deeply about issues such as the environment, architecture, inner-city renewal, and the quality of life." In a speech given for the 150th anniversary of the Royal Institute of British Architects (RIBA) on 30 May 1984, he memorably described a proposed extension to the National Gallery in London as a "monstrous carbuncle on the face of a much-loved friend" and deplored the "glass stumps and concrete towers" of modern architecture.

He asserted that "it is possible, and important in human terms, to respect old buildings, street plans and traditional scales and at the same time not to feel guilty about a preference for facades, ornaments and soft materials," called for local community involvement in architectural choices, and asked: "Why can't we have those curves and arches that express feeling in design? What is wrong with them? Why has everything got to be vertical, straight, unbending, only at right angles – and functional?"