Police Scotland have raided two properties in Glasgow as part of an investigation into the sale of illegal TV boxes to the UK licensed trade.
The criminal operation is estimated to have cost broadcasters more than £40 million across the UK over the past eight years.
For the past 16 months Police Scotland has been working with investigators from the Federation of Copyright Theft (FACT) to identify the source of the illegal operation based in Glasgow but with a network across Scotland and the UK.
Support has also come from the English Premier League as well as Sky and BT.
Chief Inspector David Pettigrew said: “The scale of this operation is significant, with an estimated 500 pubs involved but this could really be just be the tip of the iceberg.
“This illegal production scheme has been carried out in other areas across the UK but this is undoubtedly the biggest operation of its kind in the world in terms of recovery.
Pubs are attracted to the modified receivers that receive streams of overseas pay-TV broadcasts because of the perceived high cost of subscriptions to Sky and BT.
Kieron Sharp, Director General of the Federation Against Copyright Theft (FACT) said: “Pub landlords, as well as the general public, need to be aware of IPTV and set-top boxes with apps and add-ons allowing the streaming of pirated TV, sports and films are very much illegal.
Although no arrests have been made at present, officers will be reviewing the seized material and running an investigation to identify those responsible.