A £900 million antitrust lawsuit against online retail giant Amazon is set to be filed in the UK later this month, a law firm announced Thursday. This is the latest antitrust lawsuit in a string of recent suits targeting Big Tech.

The lawsuit was announced in a statement by international law firm Hausfeld & Co LLP. The suit alleges that Amazon breached UK competition law by causing millions of customers in the UK to pay higher prices for products sold on its website. Amazon is also accused of abusing its status as a dominant online marketplace by intentionally harming customers in order to make more profit.

The suit focuses on Amazon’s “Buy Box” feature, a function on its website which uses an algorithm to allow customers to easily click the link and be brought to the supposed “best deal” for the product they’re searching for. Hausfeld’s suit suggests that the “Buy Box” feature harms, rather than helps customers. “Amazon uses a secretive and self-favoring algorithm to ensure that the Buy Box nearly always features goods sold directly by Amazon itself, or by third-party retailers who pay hefty storage and delivery fees to Amazon,” the firm alleged in their statement.

The statement continued with more direct allegations of manipulation:

The Buy Box is designed and presented in a way that effectively prevents millions of consumers from navigating the site to find cheaper offers, or better delivery options, for the same product… Such manipulation of consumers is a breach of Amazon’s obligation as the dominant marketplace not to distort competition.

The plaintiff in the case is Julie Hunter, a longstanding British consumer rights advocate who will represent a class of millions of UK Amazon users. In a statement of her own, Hunter claimed:

Many consumers believe that Amazon offers good choice and value, but instead it uses tricks of design to manipulate consumer choice and direct customers towards the featured offer in its Buy Box. Far from being a recommendation based on price or quality, the Buy Box favors products sold by Amazon itself, or by retailers who pay Amazon for handling their logistics. Other sellers, however good their offers might be, are effectively shut out – relegated down-page, or hidden several clicks away in an obscure corner of Amazon’s website.

The suit is set to be filed with the UK Competition Appeal Tribunal by the end of October.