A British government agency is to order the withdrawal from sale of all supplements containing nandrolone, the anabolic steroid at the centre of dozens of positive drug tests in sport.

Olympic athletics champions Linford Christie of Britain and Dieter Baumann from Germany, Czech tennis player Petr Korda, winner of the Australian Open, and France's World Cup-winning footballer Christophe Dugarry are among those to have been banned after testing positive for nandrolone.

In Britain alone, 24 competitors from 10 different sports tested positive for the steroid in 1999-2000, with most of them protesting their innocence.

Many said they had only used legitimate supplements bought either over the counter at health food stores or by mail order.

While many such supplements do not contain banned substances, there is a rapidly growing market for products that include nandrolone precursors - chemicals that, when consumed, are converted by the body into nandrolone and which have the same medical effect as the steroid.

Sales of such products through one manufacturer are estimated to be worth more than £5 million a year.

Britain's Medicine Control Agency is now to issue notices to manufacturers in the new year ordering the products to be removed from sale, under provisions of the Medicines Act 1968.

"As far as we are concerned, nandrolone and its precursors are medicinal products and need to be licensed as such," Jane Cole, a senior official with the Medicine Control Agency said.

"Our role is to act for the safety of the public and public health. These products have significant pharmacological activity. "After receiving a complaint, we have been reviewing all products containing nandrolone and related substances. We are talking about 20 manufacturers and around 50 different products here.

"We will be writing to the manufacturers in the new year, and the chances are, since the products are to be licensed for the first time, they will become prescription-only medicines."