Tech giant Google is facing a mammoth £13.6 billion lawsuit after the UK’s specialist antitrust court agreed to merge two separate claims into a single class action suit.

The claims themselves relate to allegations that Google and its parent company Alphabet have abused their dominant position within the advertising sector to unfairly hinder their competitors.

Journalist Charles Arthur’s claim was filed behalf of 200,000 website and application publishers who claim that the US firm’s anti-competitive actions have caused them to lose out on hundreds of thousands of pounds since 2014. The second claim was filed by former Ofcom director, Claudio Pollack – who alleges similar abuses.

“Google’s abusive conduct in the ad tech market is the subject of various regulatory and legal proceedings around the world, including in the UK, and is a well-known issue,” Pollack said.

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“In keeping with its conduct in those proceedings, Google has made clear that it intends to fight this claim with all of its might, and by consolidating Charles Arthur’s and my individual claims we are able to ensure that the UK publishers are given the best chance possible for justice to be delivered.”

Google currently enjoy an unparalleled monopoly of the UK ad tech market, which the claims allege has enabled it to unlawfully restrict competition by blatantly favouring its own services – supposedly causing its rivals to lose up to 19% of the revenue they would otherwise have received since 2014.

Dismissing the claims as “speculative and opportunistic”, Google said in a statement that it “works constructively with publishers across the UK and Europe — [its] advertising tools, and those of [its] many ad tech competitors, help millions of websites and apps fund their content, and enable businesses of all sizes to effectively reach new customers. These services adapt and evolve in partnership with those same publishers.”