James Heathcote-Drummond-Willoughby, 3rd Earl of Ancaster

Gilbert James Heathcote-Drummond-Willoughby, 3rd Earl of Ancaster, (8 December 1907 – 29 March 1983), styled Lord Willoughby de Eresby from 1910 to 1951, was a British Conservative politician.

Ancaster was the son of Gilbert Heathcote-Drummond-Willoughby, 2nd Earl of Ancaster and Eloise Lawrence Breese. He was educated at Eton and Magdalene College, Cambridge. At Cambridge, he was a member of the University Pitt Club. In 1933 he was elected to the House of Commons as Member of Parliament (MP) for Rutland and Stamford, a seat he held until 1950. From 1933 to 1935 Ancaster was "Baby of the House", the youngest member of the House of Commons. He served in the Second World War as a major in the Royal Artillery, and was mentioned in despatches.

In 1951 Ancaster was summoned to the House of Lords through a writ of acceleration in his father's junior title of Baron Willoughby de Eresby. He succeeded as third Earl of Ancaster later that year upon the death of his father. Apart from his political career he was also Lord Lieutenant of Lincolnshire from 1950 to 1975 and Joint Lord Great Chamberlain from 1951 to 1983.

Lord Ancaster married the Hon. Nancy Phyllis Louise Astor (1909-1975), daughter of Waldorf Astor, 2nd Viscount Astor and Nancy Witcher Langhorne, in 1933. They had two children, one son and one daughter. His son and heir Timothy Gilbert (born 19 March 1936), went missing at sea off Corsica in 1963. Lord Ancaster died in March 1983, aged 75. On his death the earldom and barony of Aveland became extinct, while he was succeeded in the ancient barony of Willoughby de Eresby by his daughter Nancy, who also succeeded him as joint Lord Great Chamberlain. His Heathcote baronetcy was inherited by his distant relative Gilbert Simon Heathcote.