His son, the second Baron, was a successful racing driver, winning the 1949 24 Hours of Le Mans in the first Ferrari (although his codriver, Luigi Chinetti, actually drove for all but one half hour).
The Ferrari 166M in which Chinetti won was turned over to Baron Selsdon of Scotland (Peter Mitchell-Thomson) for twenty minutes during the race, making Thomson the official co-driver although Chinetti had driven twenty-three of the hours of the race.
He was married twice, firstly to Eliza Flowerdew Lowson in 1876 by whom he had one son William Mitchell-Thomson, 1st Baron Selsdon, and secondly to Eliza Lamb Cook in 1880 by whom he had two daughters.
Baron | William Cecil, 1st Baron Burghley | baron | Sacha Baron Cohen | Joseph Lister, 1st Baron Lister | Joey Baron | Robert Baden-Powell, 1st Baron Baden-Powell | Henry Brougham, 1st Baron Brougham and Vaux | Guy Carleton, 1st Baron Dorchester | William Wallace, Baron Wallace of Saltaire | William Tyssen-Amherst, 1st Baron Amherst of Hackney | James Mackay, Baron Mackay of Clashfern | Hercules Robinson, 1st Baron Rosmead | George Brydges Rodney, 1st Baron Rodney | Beechcraft Baron | Thomas Seymour, 1st Baron Seymour of Sudeley | Thomas Denman, 1st Baron Denman | Stuart Rendel, 1st Baron Rendel | Norman Foster, Baron Foster of Thames Bank | John Moore-Brabazon, 1st Baron Brabazon of Tara | Charles Cochrane-Baillie, 2nd Baron Lamington | Charles Calvert, 5th Baron Baltimore | Benedict Calvert, 4th Baron Baltimore | Baron Hans Heinrich Thyssen-Bornemisza | William Ponsonby, 1st Baron Ponsonby | Walter Rothschild, 2nd Baron Rothschild | Sidney Herbert, 1st Baron Herbert of Lea | Robert Napier, 1st Baron Napier of Magdala | Martin Conway, 1st Baron Conway of Allington | John Reith, 1st Baron Reith |
Peter Mitchell-Thomson, 2nd Baron Selsdon (28 May 1913 – 7 February 1963) won the 1949 24 Hours of Le Mans together with Luigi Chinetti in a Ferrari 166MM.