Many of her public outings involved meeting children, and on such occasions the Princess would leave her hat at home.
Claudia Acott Williams, the Kensington Palace curator, told the Daily Telegraph that Diana justified her decision by saying “you can’t cuddle a child in a hat.”
Kensington Palace is about to put on an exhibition exploring the relationship between designers and Royals.
One of the items on display will be the original sketch of a blue floral dress, by designer David Sassoon.
Diana wore the outfit regularly on visits to meet children or to hospitals.
“It could reinforce hierarchy or it could undermine hierarchy and create more of a relationship.
“This brightly coloured floral was a really important piece in her working wardrobe.”
Another of Diana’s favourite designers was Scottish-born milliner John Boyd, who made tricornes, mini-bowlers and close-fitting cocktail hats with netting and feathers for her on numerous occasions.