The heat is on: investigators discover that half the basmati rice sold in Britain is adulterated

Named after the Hindi word for "fragrant", it is prized by connoisseurs for its unique aroma and delicate taste. Such is its popularity that Britons last year consumed 190,000 tons of it.

But in the money-spinning world of basmati rice, the distinct perfume derived from Himalayan waters on the paddies of north India and Pakistan is being overtaken by a less wholesome whiff: that of fraud.

Figures obtained by The Independent, after an investigation by the Food Standards Agency (FSA), show that nearly half of all basmati sold in Britain is contaminated with inferior long-grain rice.

The result is that rather than tucking into a lightly perfumed bowl of fluffy basmati, with a lamb bhuna or monkfish tikka, thousands of discerning curry-lovers are ending up with a sticky mess created by cheaper, blander and more starchy varieties.

One leading wholesaler, who supplies convenience stores and the catering trade, said: "It's been an open secret for a long time that some disreputable suppliers are mixing other long-grain rice with basmati to make a fast buck.

"The first the consumer knows about it is when they get a saucepan of sticky rice rather than beautiful basmati. The trouble has been proving that it is the result of adulteration rather than incorrect cooking."

The FSA study of nearly 300 samples of rice sold in sizes from 250g to 20kg at outlets from supermarkets to corner shops found that nearly one in five packets had more than 20 per cent of non-basmati rice. In one in 10 cases, the adulteration reached 60 per cent.

A spokesman for the agency said: "Basmati rice ... is a premium product and therefore attracts higher prices than other long-grain rices. Telling the difference between them is difficult, and there is a profit to be made from mixing in a cheaper variety. The industry code of practice is out of date and there is a need for new standards."

The profits to be made from adulterated basmati rice are handsome. The average retail price for non-basmati long-grain rice is about 70p per kilo, compared to basmati which fetches £1.40 per kilo.

Demand for the fluffy grain, the favoured accompaniment to Britain's national dish, is also increasing rapidly, making the basmati fraud all the more lucrative. The two big global producers, India and Pakistan, last year exported 270,000 tons to the European Union, about 70 per cent of which was destined for Britain, the biggest consumer of basmati outside the Indian subcontinent. In recent years, sales have increased by 12 per cent annually, creating a market in Britain alone worth £50m. But such is the level of alarm at the adulteration problem that retailers from supermarkets to wholesalers supplying Indian restaurants are resorting to space-age means to ensure their basmati is genuine: DNA testing.

The FSA study was done by comparing samples with DNA from the 16 approved varieties of basmati, grown in five states in northern India and the western Punjab in Pakistan. As well as finding that 46 per cent of all Basmati is adulterated to some degree, the research found that almost 80 per cent either did not contain the variety advertised on the packet or it made up only a minor component.

Wholesalers and retailers, who have been threatened by the FSA with unannounced inspections to ensure their basmati is up to scratch, are now using a commercial test to ensure their product is genuine.

To date, 13 local authorities have taken enforcement action, forcing retailers to change labels or suppliers.

But one company conducting the commercial DNA tests said the adulteration problem remains. Dr Andrew Tingey, head of molecular biology at Reading Scientific Services Ltd, said: "It is fair to say the number of pure samples are in the minority. That is in part because a degree of co-mingling in the shipping and packaging processes is inevitable.

"But there are cases when the proportion of non-basmati rice can only be deliberate. Fortunately, with DNA testing we can begin to eliminate this fraud."

Leading retailers, such as Tilda, the largest supplier in the UK, already use their own DNA tests among other security measures to secure a pure basmati supply. But critics of the present regulatory regime say it encourages the adulteration problem. Under rules set by Gafta, the Grain and Feed Trade Association, the body which regulates the international rice trade, the lowest grade of basmati can legally contain up to 20 per cent of a different variety of long-grain rice.

The FSA says the new DNA technology means the threshold should be lowered to 7 per cent, forcing importers and wholesalers to improve standards.

But despite months of negotiation, the new threshold has yet to be brought in, leading to an increasing sense of frustration among those who rely on a steady supply of reliable basmati.

Abdul Miah, regional president of the Guild of Bangladeshi Restaurateurs in London, said: "We get so many rice suppliers and they fold just as quickly as they arrive. We need to keep our standards and we can do that only if the authorities ensure basmati in Britain is genuine."