Valentine traded on people's need for a normal life.

Allen Valentine's business in Wembley, with a warehouse in Watford, could produce 500,000 tablets a day.

Harrow Crown Court heard on Friday the operation was "one of the largest illegal drug and pharmaceutical production operations in Europe".

Valentine, 44, from Harrow, who admitted supplying class C drugs, was jailed for five-and-a-half years.

The court heard Valentine's "sophisticated" international operation, which also churned out steroids and cartons of potentially dangerous anti-anxiety pills, risked the health of the public and is believed to have made him millions.

Viagra and diazepam are no longer the subject of jokes. They are for many people the constituents to restore normality to the value of living. Judge Barrington Black

Just 24 hours before he was arrested, the father-of-two offered �1.25m cash for a palatial mansion in one of the country's most sought-after areas and arranged delivery of a new �26,500 Jeep Cherokee.

Valentine, of Kynaston Wood, pleaded guilty to conspiracy to supply Class C drugs between January 1, 2001 and April 21 this year, as well as two similar charges involving contraventions of the Trade Marks Act and Medicines Act.

Passing sentence Judge Barrington Black told the drugs producer, a former sales rep for Viagra maker Pfizer, that he had traded on people's need for a "normal life".

'Serious matter'

He said "considerable" sums were invested by pharmaceutical companies to develop products in a "controlled and safe" way.

"It is a serious matter when the public are hoodwinked to the extent that such products, although structurally akin to the correct ones, are being produced in an environment without the necessary precautions... in a makeshift and potentially dangerous manner.

"Viagra and diazepam are no longer the subject of jokes. They are for many people the constituents to restore normality to the value of living."

Also imprisoned was Davin Pattni, 27, of Beverley Gardens, Stanmore, Middlesex, who got three years after pleading guilty to two of the conspiracy counts.

A third defendant, Paul Austin, 40, of Hampden Road, Harrow - regarded by police as a low level "gopher" - received an 18-month sentence suspended for two years for one of the conspiracy charges he had admitted.