UK authorities are celebrating their apparent success in convincing online gambling operators not to advertise on digital file-sharing sites.

On Tuesday, the City of London Police’s Intellectual Property Crime Unit (PIPCU) claimed that its research indicated that there had been an 87% decline over the past 12 months in the number of UK-licensed gambling operators placing ads on “illegal sites that infringe copyright” of films, TV shows, books, music and games.

Last July, the UK Gambling Commission (UKGC) informed its licensees that it was implementing a new licensing condition that required operators to “take responsibility for preventing digital adverts advertising their brand from appearing on websites providing access to unauthorized content.” This new restriction, which applies not only to operators’ direct advertising but also that undertaken by third party affiliates, took effect last October.

The UKGC’s edict came after years of heavy advertising by online gambling operators on sites like Kim Dotcom’s now defunct MegaUpload cloud-storage site. Before MegaUpload was shut down by US authorities in 2012, the site was deriving roughly 1/8 of its advertising revenue just from the PartyGaming brand then owned by Bwin.party digital entertainment.