The grotto was the most famed of all the features at Oatlands, and an astonishing web of stories has been woven around its construction, authors claiming that it took forty years to build, cost #40,000 and that the masons were Italian. In fact, there were two phases of work, the first being 1762-67, and the second being 1774-78, when Joseph Lane and his son Josiah, the famous grotto-makers from Tisbury, were employed to decorate the interior. It was two storey structure, built against a bank, with three rooms and a corridor on the lower floor and one large chamber on the upper; the upper chamber could be reeded by a couple of ramps curving up from the outside. Stephen Wright was working at Oatlands for Henry Pelham Clinton, 9th Earl of Lincoln, later created Duke of Newcastle; the architect of the grotto is unknown but since Wright was superior of the works at Oatlands, and in view of this drawing coming to light, it is more than likely that he had a hand in the design. The present important section and plan evidently relates to the plan in the Osborn Collection at York University, which is dated 1766 (see M. Symes, New Light on Oatlands Park in the Eighteenth Century Garden History, vol. 9, no. 2, 1981, fig. 10). The Oaklands grotto was considered one of the finest 18th Century grotto to survive into this century and was tragically demolished in 1945