 The interior contains fine fan vaulting by Robert and William Vertue, who designed similar vaulting for the Henry VII chapel, at Westminster Abbey.The building has 52 windows, occupying about 80% of the wall space, giving the interior an impression of lightness, and reflecting the different attitudes towards churchmanship shown by the clergy of the time and those of the 12th century.The walls and roofs are supported by buttresses and surmounted by battlements, pinnacles and pierced parapets, many of which were added by George Manners during his 1830s restorations.