Microsoft faces a £1 billion ($1.27 billion) antitrust lawsuit in the UK.

The lawsuit filed with the Competition Appeal Tribunal on Tuesday claims that Microsoft is abusing its dominant position in the operating systems market to push companies to use its own cloud service, Azure. Customers who choose alternative providers are punished with higher licensing costs for Windows Server, according to the law firm.

Maria Luisa Stasi, representing the affected UK companies and organizations as the main plaintiff, stated: "Microsoft is limiting competition by steering customers towards Azure. This harms businesses and organizations in the United Kingdom.

The lawsuit is supported by LCM Funding UK, a provider of litigation funding. Microsoft itself declined to comment on the allegations.

Microsoft increasingly comes under pressure from competitors who criticize the company's licensing terms.

The CMA found in a study that AWS is the leading provider of cloud services in the UK, while Microsoft and AWS together generate the majority of revenue in the cloud software market. Microsoft argued in a hearing in July that despite having a smaller market share, Google's cloud platform has significant advantages. Additionally, the company emphasized that competition between providers is intense and leads to lower prices.