In 1931 Williams-Ellis bought from his uncle, Sir Osmond Williams, Bt, the Victorian crenellated mansion Castell Deudraeth with the intention of incorporating it into the Portmeirion hotel complex, but the intervention of the war and other problems prevented this. Williams-Ellis had always considered the Castell to be “the largest and most imposing single building on the Portmeirion Estate" and sought ways to incorporate it. Eventually, with support from the Heritage Lottery Fund and the European Regional Development Fund as well as the Wales Tourist Board, his original aims were achieved and Castell Deudraeth was opened as an 11 bedroom hotel and restaurant on 20 August 2001, 23 years after Williams-Ellis's death, by the Welsh opera singer Bryn Terfel.