If Prince Charles wants to buy perfume for his future Queen for Valentine’s Day next week, he may have to play a guessing game.

Although perfumers have identified the majority of the royals’ favourite smells, they have yet to identify the mystery perfume worn by Camilla, Duchess of Cornwall.

And, by all accounts, she’s picky about what she dabs behind her ears, once refusing a gift from Charles and instructing him to give it to an attendant instead.

After her Majesty announced that she wanted Camilla to be the next Queen, Prince Charles will be hard pressed to find anything that compares to the promise of wearing a coronation crown set with the legendary 105-carat Koh-i-Noor diamond.

The correct perfume can say a lot, but he must walk carefully since, according to noted fragrance expert Rob D Blandford, fragrance choices are very personal and reflect age and personality.

And, according to royal gossip, Charles, who wears the most costly perfume of all the royals, has previously made a blunder when he returned from an engagement with a bottle of perfume for Camilla that had been given to him as a gift.

According to insiders, Camilla took one glance at it and wrinkled her nose, telling him it was a “disgusting” perfume and suggesting he give it to a female staffer with whom she reportedly did not get along.

If he wants to make an educated estimate, he should definitely ignore 1970s favourite Charlie and try flowery because this is the most popular scent profile across all royal fragrances evaluated by Showerstoyou.co.uk experts.

Floral notes like jasmine and iris accounted for 42% of the total number of notes studied in their royal smell survey.

Royals also appear to prefer earthy aromas such as musk, amber, and sandalwood, which accounted for 28% of the total notes.

Younger members of the family prefer fresh aromas like lemon and bergamot, and their selections even included food scents like cassis, tonka bean, coriander, and rosemary.

Prince Charles: Green Irish Tweed by Creed £245

Charles is believed to have costly tastes and to wear Green Irish Tweed, which costs roughly £245 per bottle.

The aroma is defined as a “reference to the House of Creed’s artisan’s equestrian tailoring past,” and it is the most expensive of all the royals’ favourite scents.

It is comparable to the perfect, 19th century gentleman’s country tweed” and is described as “refined, timeless, and effortlessly manly” with the perfect amount of nostalgia.”

According to the advertisement: “This traditional men’s scent captures the spirit of a prestigious gentleman’s estate. Green Irish Tweed adds the finishing touch to hunting parties, hip flasks, and horseback rides through the verdant countryside.”

Princess Diana wore Quelques Fleurs by Houbigant Paris at £130

Princess Diana also had expensive perfume tastes, and she famously poured part of it on her wedding gown before leaving for St Paul’s Cathedral.

According to reports, Houbigant’s Quelques Fleurs is remarkably similar to one of the Queen’s favourites and was made in the same era: Paris in 1913.

Rob claims that the base contains synthetic crivet, an extract derived from African wild cats.

“Civet makes floral perfumes alluring and sexy. renders florals almost 3D and makes the wearer seem mysterious, glamorous, and definitely someone to notice,” he said.

“Based on their fragrance choices, we could interpret that both the Queen and Diana have natural royal qualities: confidence, largesse, are happy to be in the spotlight, be noticed, be the centre of attention.”

Kate Middleton: White Gardenia Petals by Illuminum £125

This is described by the makers as a “delicate, refined scent” that is sumptuous and feminine, it has lily, gardenia, ylang ylang, jasmine and amber wood in the light bouquet. Fragrance expert Rob noticed that Kate and Meghan’s choices are “substantially more restrained and discrete” than the Queen and Diana’s preferences. “One could even say minimal, pared back, and practical,” Rob said. “Clean, inoffensive, almost unnoticeable.” He said Kate also loves Orange Blossom by Jo Malone which is unisex and very safe with wide appeal. “It is not a perfume for a risk-taker,” he said. “It is very much of its time and would never dominate a room or draw too much attention to its wearer.”

Princess Anne: Calèche by Hermès £113

This perfume, which dates back to 1961 and was Hermes’ first scent for women, is described as a highly feminine smell in which the grandeur of iris is highlighted by ample sandalwood.

Perhaps Anne was drawn to it since the name alludes to the company’s characteristic horse-driven carriages.

Prince William: Blenheim Bouquet by Penhaligon’s £110

This is also a perfume firm that is proud of its royal links and reminds couples that “love is best expressed via aroma.”

Queen Elizabeth II: White Rose by Floris £80

According to the English heritage brand, Florence Nightingale was a fan of this ancient fragrance, and naval hero Lord Nelson purchased it for his mistress, Lady Hamilton. Floris bears the royal insignia and Prince of Wales feathers, indicating that it is a brand preferred by HRHs.

According to some, the Queen also enjoys wearing Guerlain’s L’Heure Bleue Eau de Parfum. According to Rob, who studied at the Grasse Institute of Perfumery in the south of France, this smell worn by French actress Catherine Deneuve is not for shrinking violets and would help the Queen command the space.

He said: “It is a monumental French composition, multi-layered and deeply complex with a host of tropical florals, spices on a rich, dense base of iris, vanilla and sensual woods. It is truly a grand fragrance, which attracts attention and creates an air of mystery while remaining classic and firmly rooted in early 20th Century Old World style.”

Princess Margaret: Oscar by Oscar de la Renta £68

This debut perfume by Oscar de la Renta is defined as a classic, floral, slightly sharp scent with aromatic notes of lavender, rosemary, and carnation, with sweet, powdery, and musky base notes.

Meghan Markle: Côte d’Azur by Oribe £60

Meghan appears to enjoy fresh unisex scents, and Côte d’Azur is a modern perfume that can be worn by both men and women.

Meghan, it appears, also enjoys a Jo MaloneWood Sage and Sea Salt fragrance.

“Once again a unisex formulation, this smell is salty and clean, evoking an ocean breeze,” Rob explained. Almost no one will be offended by this aroma.”

Prince Harry: Cool Water by Davidoff £54

While Meghan likes a unisex scent, husband Harry was known of preferring a very masculine smell.