The Mexican national, who has a US passport, is the latest in a series of bogus businessmen selling counterfeit drugs to be prosecuted by the medication watchdog, the Medicines and Healthcare products Regulatory Agency (MHRA).

The MHRA launched an operation known as Stormgrand following complaints from a number of disgruntled customers who complained that the anti-impotence tablets were fake and had no effect.

The operation was one of the biggest of its kind in the UK and saw £1.5million's worth of counterfeit medicines made in illicit factories in China, Pakistan and Asia seized including erectile disfunction drugs Viagra and Cialis and baldness treatment Propecia.

Some counterfeit Cialis had already made its way into the NHS supply chain, leading to a UK-wide product recall.

Patino initially stood trial last year alongside other members of the drug smuggling gang but the jury failed to reach a verdict in relation to the charges he faced.

Shortly before he was due to be retried, he pleaded guilty to a charge of conspiring to sell counterfeit Viagra, making $237,000 (£133,000) in the process.

Kingston Crown Court was told that Patino was in league with the lynchpin of the operation Ashish Halai, 34, of Borehamwood, Hertfordshire, who was jailed for four-and-a-half years last year.

Instead of the medicine arriving in the manufacturer Pfizer's packaging, the counterfeit pills were delivered to customers in brown bottles.

Patino received numerous complaints from buyers, including one that claimed the product was coated with blue paint which was coming off the tablet.

He was arrested by MHRA investigators who had been tracking the gang when he arrived at Heathrow Airport in October 2005.

His laptop was seized along with a memory stick which revealed files of his business dealings and over 2,000 digital photographs depicting or associated with pharmaceutical products. The huge amount of fake tablets he was peddling earned him the title the "King of Viagra" among his associates, investigators said.