The ‘miracle fruit’ has become the toast of the culinary elite for its ability to change the way your mouth works to make sour things taste sweet.

At first glance, it looks and tastes much like an ordinary red berry.

Native to West Africa, the synsepalum dulcificum is not much bigger than a grape and, other than an attractive red skin, is unassuming.

It’s being called the "miracle fruit" for the way it seems to make sour flavours magically become sweet.

The berry contains a glycoprotein that temporarily masks your mouth’s ability to taste sour and bitter notes. Once the berry’s pulp is swilled around the mouth and the large stone spat out, lemons suddenly taste like sugary lemonade, vinegar takes on a peculiar treacly tang and Irish stout tastes similar to a chocolate milkshake.

In New York and San Francisco, the latest fashionable trend is to spend an evening "fruit dropping." Partygoers chew berries or pop pills of dried pulp (perfectly legal) before wolfing down quantities of seemingly metamorphosed foods.

In Britain, demand for the fruit has grown to the extent that the country’s two main suppliers have warned customers they might have to wait weeks.

Chas Barr, a former IT specialist from South London, began selling berries through his website miraclefruit.co.uk after reading about them eight months ago on a botanical blog.

Demand has soared.

"In the past couple of weeks it has gone nuts. I’m selling thousands of pounds worth in a week."

Although the effect has yet to be backed up by scientific evidence, fruit growers say miracle berries are popular with chemotherapy patients because they help diminish the unpleasant aftertaste that comes with treatment.