Microsoft buying Activision Blizzard could reduce competition, says the UK watchdog.

The Competition and Market Authority has concerns about the tech giant buying the parent company of ‘Overwatch’, ‘Candy Crush’ and ‘Call of Duty’.

In response, Microsoft said they were willing to work with the CMA on the “next steps” to make their deal happen, which would be the largest in their history.

In the ruling, the CMA expressed concerns about the problems it could cause for their competitors, such as Sony.

Sorcha O’Carroll, the CMA’s senior director of mergers said: "Microsoft could use its control over popular games like Call of Duty and World of Warcraft post-merger to harm rivals.

"If our current concerns are not addressed, we plan to explore this deal in an in-depth Phase 2 investigation to reach a decision that works in the interests of UK gamers and businesses."

Phase 1’s completion comes before the second phase, which will see an independent panel to look at the deal more in detail.

Brad Smith, a Microsoft spokesperson said: "We're ready to work with the CMA on next steps and address any of its concerns. 

"Sony, as the industry leader, says it is worried about Call of Duty, but we've said we are committed to making the same game available on the same day on both Xbox and PlayStation. We want people to have more access to games, not less." 

The company - which was founded by Bill Gates - argue they want to purchase the company for their expertise within the mobile game sphere and have denied prohibiting titles like ‘Call of Duty’ from other consoles, such as Sony’s Playstation.

Last month, Saudi Arabia became the first territory to approve the deal between the two companies.