Desmond was the youngest of the five children of the Reverend Robert Ffrench-Blake and his wife, Mary Elizabeth Hewitt. He was born in Eastry, Kent.
He was educated at St. Hugh’s, Chislehurst and Eton. He matriculated in 1919. One of his brothers had been killed in action in 1917.
Like many of his family, he was commissioned into the 13th/18th Royal Hussars and was with them at Risalpur, India prior to the War.
On 1 August 1939, he married Elizabeth Iris Cardale. They had a son born in June 1940.
He was commanding the 2nd Lothians and Border Horse in Tunisia when he was killed, accidentally, on 31 May 1943, shortly after the capitulation of the German Army.
He is buried in Enfidaville War Cemetery, Tunisia Plot IV. A. 2.
He is commemorated on the War Memorial at Davenham, Cheshire.
His wife remarried in 1951 and died in 1963.