(Sharecast News) -

A £13.6bn lawsuit brought against Google over its dominance in the online advertising market will go ahead, a UK court ruled on Wednesday.

The case has been brought by a group called Ad Tech Collective Action LLP, which has accused the tech giant of anti-competitive practices that have harmed online publishers.

In response, Google parent company Alphabet called the case "incoherent" as it tried in vain in its attempts to get the legal action dropped. However the Competition Appeal Tribunal in London ruled the case could now go to trial.

"This is a decision of major importance to the victims of Google's anti-competitive conduct in adtech," former Ofcom director Claudio Pollack, now a partner in Ad Tech Collective Action, told the BBC.

The cases cover advertising technology, usually shortened to adtech, which decides which online adverts people see, as well as how much they cost to publishers.

Hosting these advertisements is a large source of revenue for many websites - Ad Tech Collective Action says digital advertising spend reached $490bn in 2021.

It is also an extremely valuable industry for Google, because it dominates web search so heavily.

At the core of the claim is the allegation that Google is abusing that dominance, reducing the income websites get. Ad Tech Collective Action says Google has engaged in what is known as "self-preferencing" - in other words promoting its own products and services more prominently than that of its rivals.

"I look forward to working with our legal and economic advisers to deliver compensation for years during which the relevant markets did not provide a competitive outcome for the UK publishing market," Pollack said.

However, the case has been bogged down for 18 months, with no court date set. Google is already facing probes by regulators in the UK, Europe and US into its adtech business.

Reporting by Frank Prenesti for Sharecast.com