Queen Elizabeth in mourning after the death of one of her closest aides

The Queen is mourning the loss of one of her closest members of staff. Photo / Getty Images

Queen Elizabeth is in mourning following the death of one of her most trusted aides.

Ann Fortune FitzRoy, the Duchess of Grafton, served as the monarch's Mistress of Robes - a role which put her in charge of all matters relating to the queen's jewellery and clothes, as well as arranging the rota of attendance for ladies-in-waiting, and other duties at state ceremonies - from 1967 until her death on Friday, December 3 at the age of 101.

The duchess began working for the royal household in 1953 as a Lady of the Bedchamber before being appointed as Mistress of the Robes in 1966.

She was described by Histoires Royales as "the most loyal friend and aide" and travelled with the Queen on numerous royal tours, including Nigeria in 1956, France in 1972, Morocco in 1980 and Russia in 1994.

The duchess - who was born in 1920 to Captain Evan Cadogan Eric Smith MC and his wife Beatrice Helen Williams - initially trained as a nurse at Great Ormond Street Hospital before marrying the then-Earl of Euston Hugh Fitzroy, who later became the 11th Duke of Grafton and died himself in 2011.

He went on to be succeeded by his grandson Henry Fitzroy, 43, who has served as the Duke of Grafton ever since.

The queen acknowledged the duchess's services by making her a Lady Grand Cross of the Royal Victorian Order in 1980 - an honour normally reserved strictly for members of the royal family.

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The tragic news of her passing comes just months after the queen lost her husband Prince Philip, who died in April at the age of 99 following a marriage of 73 years.

The Duke of Edinburgh's passing left a "huge void" in the queen's life.

Their son, Prince Andrew, previously said: "The queen as you would expect is an incredibly stoic person. She described his passing as a miracle and she's contemplating, I think is the way that I would put it. She described it as having left a huge void in her life but we, the family, the ones that are close, are rallying round to make sure that we're there to support her."