‘Heliotropin,’ said the Frenchman mournfully. I was midway through lunch in Mayfair with Benoit Brosseau, whose father, Jean-Charles, created the fragrance Ombre Rose, and who now leads the company of the same name. I had asked the question I always put to fragrance people, in the full knowledge it will make them either sad or furious: how do they cope with Ifra, the Brussels-based regulatory, or representative, body of the fragrance industry?

One of the latest in the list of ingredients Ifra may be curbing is based on heliotrope, which not only gives a powdery aspect to scent, but conjures up the elusive smell of cherries. (If you know that marvellous, evocative Guerlain scent L’Heure Bleu, that has it.) M. Brosseau was fed up. In common with every good fragrance maker, he’s hemmed in by a list of regulations about what can go in his scent that gets longer and more onerous with every amendment.

Ifra has most recently introduced its 51st amendment, which restricts the use of 48 ingredients, chiefly because of concerns about potential effects like skin sensitisation. Weirdly, the same regulations apply to fabric softener for sheets and moustache conditioner as, say, Guerlain perfume. And while no one will shed tears if their pillow spray is reworked, you want to talk to perfume buffs to appreciate the full extent of human fury after a favourite scent is modified. Get fragrance fanciers together and the names come up of famous perfumes that aren’t what they used to be.

Some of the modifications are reasonable and some aren’t to do with Ifra: one historic ingredient was derived from the secretions of the perineal glands of the civet, giving a notable animalic note to scents like Jicky – and few will go to the barricades on that one. But the rules affect any number of important ingredients and the concentration levels that are used in them.

Roja Dove, a marvellous scent-maker, says with barely concealed irritation: ‘Basil has for years been considered this dangerous material in specific concentrations, but how about rules to protect all the chefs who are chopping basil up for pesto, in greater quantities than you’d ever use in a scent? It’s simply not rational.’ So what ingredients can’t he use properly? ‘How about all of the mosses, crucial to chypre scent?’ he says, tartly.

To get your head around the effect of the industry regulations, imagine artists being banned from using, say, indigo or lemon yellow. They’d find ways around it, of course, but it would cramp their style. Or take chefs who had to take into account every possible allergen. Imagine conjuring up a menu where nuts, dairy, eggs and wheat were all proscribed or progressively restricted because someone, somewhere (almost certainly in America) found these things brought them out in boils. It would dampen their vital spirits.

You want to talk to perfume buffs to appreciate the full extent of human fury after a favourite scent is modified

Naturally Ifra itself maintains that it is acting in defence of perfumers. Lisa Hipgrave, the director of Ifra UK, tells me that it ‘cares very much about consumer safety’. ‘Ifra does set standards, however [its] standards are not a legal requirement and only mandatory to Ifra members.’

What would happen if a perfumer went wild with oakmoss, heliotrope and tonka bean? If you had ignored the regulations, you’d be in a bad place if someone took you to court for bringing her out in a rash. And you wouldn’t have the all-important paperwork for export to the US.

Linda Pilkington of Ormonde Jayne, (Levant! Isfahan! Montabaco!) says that trouble comes when the new regulations affect existing scent, often by restricting the concentration of ingredients: ‘We have to rework the formula but only if it can be the same smell. If it’s too off, we won’t stock it.’ She has nine of what she calls Sleeping Beauties, perfumes no longer available for that reason. She gets mobbed by fans asking when Black Gold or Tiare (problem element: Tahitian gardenia) is coming back.

Thierry Wasser, one of the great French perfumers, pointed out in a spirited encounter with Ifra last year, ‘the difficulty of applying regulatory tools originally developed to protect workers dealing directly with high-volume industrial chemicals, but which are now being used to regulate complex fragrance mixtures used in very small quantities’. That gets to the nub of the matter. He also spelled out ‘the creative, sensory and technical functions of the many hundreds of materials in a perfumer’s palette, and how each contributes to the balance and performance of a fragrance and that removing or changing one material impacts the entire architecture of a scent’.

There is an obvious solution: list the ingredients of a scent on the box and let the buyer note and beware. Or else issue scent in two variants: one for hypoallergenic Americans, another for the rest of us. But that would be just too simple, wouldn’t it?