OXFORDSHIRE trading standards officers have warned people they could end up with harmful fakes if they try to buy prescription drugs over the Internet.

The county's officers have been buying drugs like Viagra, Tamiflu, Prozac and Valium from foreign websites but some have turned out to be bogus or contaminated.

Nigel Strick, the council's trading standards manager, said taking drugs without a prescription could be extremely dangerous.

He added: "We warn people that it is most inadvisable to seek to obtain such drugs without proper medical guidance and a prescription. They are playing a dangerous game of Russian roulette if they do.

"And, beyond that very real danger, there is also the risk that the drugs ordered in this way may not arrive at all or could be counterfeit and it would be extremely difficult to get your money back from a seller based abroad."

Misuse or excessive doses of those drugs could have serious and even fatal health consequences, the Royal College of General Practitioners said.

Some of the 20 drugs ordered online arrived with no instructions for use. Three of them came with no supplier or manufacturer information. Others failed to turn up at all.

Oxfordshire trading standards officers ordered ten prescription-only drugs from websites based in countries such as Canada, Panama and India.

Fertility drug Clomid and Diazepam, also known as Valium, both arrived in Jiffy bags with no instructions, warnings or dosage directions.

Other samples of Viagra, Tamiflu, Prozac and Valium appeared to be genuine.

One £54 order for ten Viagra tablets failed to turn up six weeks after the money had been paid. Another sample did arrive but was sent for testing because it seemed fake.

Meanwhile, Worcestershire trading standards officers ordered the drugs online from countries such as Peru and Thailand. Four of those had still not arrived one month after payment.

Three samples of Clomid arrived with no supplier or manufacturer information. Another three samples of Prozac, Viagra and Diazepam were sent for testing.

The sale of medicines in the UK is regulated by the Medicines Act 1968, but overseas suppliers are not subject to these controls.

Mick Deats, head of enforcement and intelligence at the Medicines and Healthcare Products Regulatory Agency, said the sale and supply of counterfeit medicines is on the increase. "Criminal gangs are targeting consumers via the Internet, in pubs and clubs and through illegal advertising," he warned.

Customers who buy prescription drugs via the Internet have no protection if they are dealing with firms based in countries that do not have legal agreements with the UK.