I n a corner of Covent Garden, well-heeled Londoners and tourists browse the range of frankincense products sold by a leading cosmetics brand while they drink a complimentary rose and berry tea. Amid the aromatic resin sheathed under glass, shoppers can buy “age-defying” serums, creams and essences, and tablets to strengthen brittle nails and hair. At one counter, a sales assistant is advising customers on how much of the essential oil to add to their nebuliser to make guests feel relaxed “without overwhelming them”.

Another explains frankincense’s “hydrating and rejuvenating” properties, including its alleged ability to smooth out fine lines caused by smiling and squinting. In terms of popularity, she says, it now far outstrips lavender, tea tree and other botanicals. “Frankincense is our signature product – our bestseller,” she says.

It also fetches high prices. Here, a 50g bottle of frankincense firming cream costs upwards of £80, as does a 15ml vial of eye serum from a line sold next door. In another shop, a luxury French brand sells “virile” perfumes infused with frankincense for hundreds of pounds a bottle.

An American aromatherapy company hails frankincense as the “king of essential oils” and claims it can promote cellular health and immunity. Their 15ml bottles retail at $115 (£88). Frankincense has been harvested in the Horn of Africa and across the Red Sea in the Arabian peninsula for millennia.

In ancient Egypt, it was prized for its d.