The castle remained the property of the Clarendons until 1937, when Lord Clarendon found the maintenance of the castle too expensive and sold Kenilworth to the industrialist Sir John Siddeley.[1] Siddeley, whose tax accounting in the 1930s had been at least questionable, was keen to improve his public image and gave over the running of the castle, complete with a charitable donation, to the Commissioner of Works.[123] In 1958 his son gave the castle itself to the town of Kenilworth and English Heritage has managed the property since 1984 and is open to the public.[124][125] The castle is classed as a Grade I listed building and as a scheduled monument.[126]