British landowner and Liberal politician. He inherited the Willoughby de Eresby estates and was created Earl of Ancaster in 1892. He was a joint hereditary Lord Great Chamberlain of England and held public offices connected with Lincolnshire.

The identification of the 1896 Earl of Ancaster as Gilbert Henry Heathcote-Drummond-Willoughby is based on the date of creation of the earldom and his lifetime; the directory itself names him only by title.

Research sources:
- Kelly's Directory of Lincolnshire, 1896, entry for Aby: 'The Earl of Ancaster P.C. who is lord of the manor'. Digitised historical directory accessed through the University of Leicester Special Collections. — https://forebears.io/england/lincolnshire/aby
- Wikipedia biographical reference — https://en.wikipedia.org/wiki/Gilbert_Heathcote-Drummond-Willoughby,_1st_Earl_of_Ancaster