Set with more than 800 stones, the tiara is held on its frame by tiny wing-topped screws, allowing the central three sections to become a choker necklace and the two outer sections joining to form a bracelet.
It was given to Lady Delia at her marriage on February 18, 1914, to the Hon Sidney Peel, younger son of the 1st Lord Peel, Speaker of the House of Commons and grandson of Prime Minister Sir Robert Peel.
The outline of the tiara can be made out under the veil in her wedding-day photograph and it was mentioned among the gifts listed in The Times’ report of the wedding: ‘From Earl Spencer: a diamond tiara’. It was offered for sale on behalf of a descendant.
The life of the erstwhile owner is chronicled in A Memoir of the Lady Delia Peel, born Spencer, 1889-1981 by Priscilla Napier, a copy of which was offered with the lot.