Hilda Blenkinsopp is a non-canonical character who was created for the ITV's 2010 adaptation of The Secret of Chimneys. She is an official with "National Heritage" and is very set on buying over "Chimneys" for the purposes of converting it into an attraction to be opened to the public. Lord Caterham invited Blenkinsop for the house party in order to fill out the guest list for a house party but Bundle who opposes the sale of her family home is hostile to her presence. When the main guest Count Ludwig von Stainach is murdered during the house party, Blenkinsop also becomes a suspect since the Count also wanted to buy Chimneys and could thus have been in her way.
As the investigation into the murder proceeds, Bill Eversleigh catches Blenkinsopp searching through the household documents, in particular the household accounts of 1932. Bundle accuses Blenkinsopp of always working to undermine Lord Caterham's ownership of Chimneys, by alerting his creditors, for example. But Blenkinsopp's link to Chimneys, like that of many other people at the house party, goes deeper than that, and relates to the a party at Chimneys in 1932 when a jewel had been stolen and Agnes Parker, a parlour maid, had gone missing.
Hilda Blenkinsop is portrayed by Ruth Jones.