Ethel was born 8 June 1879 as the second child of Herbert Warneford Thomson, surgeon, and his wife, Sophia Charlotte Bond.

[2] In 1912 she became Wimbledon champion by first defeating Charlotte Cooper Sterry in the All-Comers' final and subsequently receiving a walkover in the Challenge Round.

Her partner James Cecil Parke misjudged a smash in the second set which hit her full on the side of the face and the resulting eye injury forced her to retire from the mixed doubles final and to default from her challenge round match against Dorothea Lambert Chambers scheduled for the following day.

[5] In 1903 A. Wallis Myers wrote that her favorite shot was the backhand down the line and that she possessed an effective smash.

[6] According to Dorothea Lambert-Chambers she was one of the best female volleyers of her time but did not have a very good condition, causing her to fade in matches.