Amazon is facing a massive lawsuit in the UK over claims it unfairly favors and promotes its own products.

Gatekeeper companies that sell their own products and services, while also providing a means for competitors to do the same, are coming under increased scrutiny. Apple and Amazon are two such companies that have both been accused of unfairly favoring their own products over those of the other companies that sell via their platforms.

According to Reuters, Amazon is facing a $1 billion lawsuit in the UK over such accusations. The case is being brought by consumer rights advocate Julie Hunter.

“Far from being a recommendation based on price or quality, the Buy Box favours products sold by Amazon itself, or by retailers who pay Amazon for handling their logistics,” Hunter said in a statement. “Other sellers, however good their offers might be, are effectively shut out.”

Amazon has disputed the merits of the case:

“This claim is without merit and we’re confident that will become clear through the legal process,” a company spokesperson said.