A lawsuit has been filed in opposition to Google to hunt £3.4bn ($4.2bn) in compensation for publishers for misplaced income.

The declare, by ex-Guardian expertise editor Charles Arthur, alleges Google unlawfully used a dominant place in on-line adverts in a means that lowered what publishers may make from them.

Google stated it will struggle the “speculative and opportunistic” motion vigorously.

It’s the second such lawsuit, after an analogous case was launched in November.

That was introduced by former Ofcom director Claudio Pollack, who’s searching for as much as £13.6bn in damages from the tech large.

The circumstances concern promoting expertise – adtech – that decides in a fraction of a second which on-line adverts customers will see, how a lot they’ll price, and the way a lot publishers will earn.

On-line show promoting is the primary supply of earnings for a lot of web sites.

The UK competitors regulator, the Competitors and Markets Authority (CMA), can be investigating Google’s dominance in promoting expertise.

Within the lawsuit, which was filed on Thursday, Mr Arthur claims that due to Google’s abuse of its place, the costs of adtech companies had been inflated, and advert gross sales revenues of publishers had been unlawfully lowered.

“The CMA is presently investigating Google’s anti-competitive conduct in adtech, however they don’t have the ability to make Google compensate those that have misplaced out. We will solely proper that unsuitable via the courts, which is why I’m bringing this declare,” he wrote.

Each authorized claims ask the court docket – the Competitors Enchantment Tribunal – to certify their claims as “opt-out”, that means each related writer can be routinely included within the case except they select in any other case.

These are collective claims, also known as a category motion in the US, which solely grew to become doable within the UK in 2015. As a result of they’re introduced on behalf of an entire group or class, the damages could be very giant.

Except Mr Arthur and Mr Pollack comply with collaborate, the tribunal should resolve which one ought to lead the collective declare

Google has stated that its promoting instruments, “and people of our many adtech opponents, assist tens of millions of internet sites and apps fund their content material, and allow companies of all sizes to successfully attain new prospects”.

Though the CMA discovered that Google owned the most important supplier in three key areas of adtech, the agency maintains it has many opponents. It additionally says its adtech charges are decrease than, or match, trade averages.

However in a case launched in January, the US Justice division accused Google of being an “trade behemoth” that had “corrupted authentic competitors within the adtech trade by participating in a scientific marketing campaign to grab management of the extensive swath of high-tech instruments utilized by publishers”.

On Tuesday, Google requested a court docket to dismiss the case – arguing that the US authorities had overstated its maintain in the marketplace.

In 2021 the French competitors regulator, Autorité de la concurrence, fined Google €220m for favouring its personal companies within the internet marketing sector.