 His only son and heir Timothy, Lord Willoughby de Eresby, went missing at sea in 1963.As a result, on Lord Ancaster's death in 1983 the barony of Aveland and earldom became extinct while he was succeeded in the barony of Willoughby de Eresby by his daughter Nancy.The Heathcote Baronetcy also survived, and was inherited by the late Earl's kinsman, the ninth Baronet.