Police and Trading Standards have recovered more than £1.5m worth of counterfeited goods during raids on a market in Wembley, north London.
Pirated DVDs were among the counterfeit goods
The raids, called Operation Dawn, took place over the last month and also involved Immigration Service and Patent Service staff.
The counterfeit goods included pirated CDs and DVDs.
Two people were arrested for selling pirated goods, and a number of suspected illegal immigrants were held.
"Each raid netted a high volume of counterfeit goods, disrupted the illegal traders' networks and allowed legitimate market traders do business without having to compete with cut-price fakes," the Department of Trade and Industry said.
The raids were the first to be carried out by the National Intellectual Property (IP) Crime Group.
The group was launched last year as part of a wider strategy against intellectual property theft.
Lord Sainsbury, Innovation Minister, said: "The National IP crime strategy has dealt the first blow to the pirates.
"Seizing more than £1.5m worth of goods and hitting the crime networks that support the sale of counterfeit goods is a significant step forward in tackling the threat to legitimate business posed by pirated goods."