James Radclyffe, 3rd Earl of Derwentwater

James Radclyffe, 3rd Earl of Derwentwater (26 June 1689 – 24 February 1716) was an English peer who participated in the Jacobite rising of 1715 and was executed for treason.

Life Radclyffe was the son of Edward Radclyffe, 2nd Earl of Derwentwater and Lady Mary Tudor, the natural daughter of Charles II by Moll Davis. He was brought up at the exiled court of St Germain as a companion to the young prince, James Francis Edward Stuart (the 'Old Pretender' after his father James II died), and remained there at the wish of Queen Mary of Modena, until his father's death in 1705. He succeeded to the family titles and estates in Northumberland on the death of his father in 1705.

After that, he travelled on the continent, sailed from Holland for London in November 1709, and then set out to visit his Cumberland estates for the first time early in 1710. He spent the next two years at Dilston Hall, Northumberland, the mansion built by his grandfather on the site of the ancestral home from 1521; the estates were sequestrated after the Civil War due to the recusancy of his grandfather the first Earl. He regained those and began the construction of a grand mansion to replace the old Hall, a task that was never completed.

On the day of his execution, the Northern Lights were said to be unusually bright, and became known as Lord Derwentwater's Lights. His heart was taken to a convent in Paris where the prioress Anne Throckmorton witnessed it being enclosed within the chapel's walls.

Derwentwater was stripped of his honours and titles (but his successors continued to use the titles), and his estates were confiscated. In 1748 Dilston Castle and the rest of the Derwentwater estates were granted by Act of Parliament (22 Geo. 2. c. 56) to the Greenwich Hospital.

Family Radclyffe married Anna Maria Webb (d. 19 August 1723) on 10 July 1712. She was the eldest daughter of Sir John Webb, 3rd baronet, of Odstock, Wiltshire, by Barbara, daughter and coheiress of John Belasyse, 1st Baron Belasyse. they had three daughters and one son Robert Petre, 9th Baron Petre.

Lady Derwentwater and her children fled to Brussels in 1721, and she died there of smallpox in 1723.

Legacy Radclyffe's death is recounted in two English traditional ballads: "Lord Derwentwater", collected by Francis James Child and published as Child Ballad 208 in English and Scottish Popular Ballads (1882–98). "Lord Allenwater", collected by Ralph Vaughan Williams in 1904 from the singing of Emily Stears.

Radclyffe figures prominently in the historical novels Dorothy Forster by Walter Besant and Devil Water by Anya Seton.

In October 2022, a bedsheet embroidered with human hair, by Radclyffe's wife, in his memory, was displayed at the Museum of London, which acquired it in 1934. The museum stated that the hair "could have come from her own head or that of the earl, or she could have intertwined a combination of the two".