The company, which is a key player in the online advertising market as well as a dominant force in search, is accused of abusing its market power in ad technology, which coordinates the sale of online advertising space between publishers and advertisers. “Publishers, including local and national news media that play a vital role in our society, have long been hurt by Google’s anti-competitive behavior,” said Damien Geradin, of the Belgian law firm Geradin Partners involved in the EU case. “It’s time for Google to take responsibility and pay back the damage it has done to this important industry. That is why today we are announcing these actions in two jurisdictions to obtain compensation for EU and UK publishers.” British law firm Humphries Kerstetter plans to take a case to the Competition Appeal Tribunal next month, although the process could take years to complete. The UK competition authority is also investigating Google’s power in the digital advertising technology market. Toby Starr, a partner at Humphries Kerstetter, said the claim, which aims to recover ad revenue lost to Google’s alleged anti-competitive behavior over a period of years, would not simply benefit news sites. “This significant claim will represent a class of victims of Google’s anti-competitive behavior in ad technology who have collectively lost around £7bn. This includes news sites up and down the country with large daily readerships, as well as thousands of small business owners who depend on advertising revenue – whether from their fishing site, food blog, football fanzine or other dedicated online content time to create and publish.” Subscribe to the Business Today daily email or follow Guardian Business on Twitter @BusinessDesk A UK claim will be “opt out”, meaning that affected parties will automatically be treated as part of the claim, while an EU claim submitted to the Netherlands will be “opt in”, meaning that would-be claimants they must apply to join the suit. Starr said he expected “many thousands” of parties in the UK to join the bid. The combined lawsuits seek total damages that legal representatives estimate could reach 25 billion euros. The lawsuits are funded by litigation funding companies in the UK and the Netherlands, which take a cut of any proceeds from a successful case. Contacted for comment, Google referred the Guardian to its statement about the Competition and Markets Authority’s (CMA) investigation, which said: “Advertising tools from Google and many competitors help websites and apps fund content and help businesses of all sizes reach customers effectively. Google’s tools alone have supported around £55bn in economic activity for over 700,000 UK businesses and when publishers choose to use our advertising services, they keep most of the revenue. We will continue to work with the CMA to answer their questions and share the details of how our systems work.”