Microsoft will have to endure prolonged investigations in the UK and Europe before its Activision Blizzard merger can take place.

The UK's Competition and Markets Authority (CMA) has said its inquiry may expand into a second phase due to numerous antitrust concerns.

The CMA is concerned about the impact the proposed deal will have on PlayStation's ability to compete, with Xbox gaining ownership of the Call of Duty series.

Thus far, Microsoft has been unable to quell these concerns, and so the Financial Times reports that CMA is likely to officially expand its investigation this week.

The report also suggests that we'll be seeing a lengthy EU probe once Microsoft officially files its case in Brussels.

Just last month Xbox CEO Phil Spencer, said he felt "good about the progress that we’ve been making," and that "the discussions we’ve been having seem positive."

As the inquiries drag on, we can't help but wonder if he feels the same today.

The companies plans for the Call of Duty franchise are of chief concern to regulators, Spencer has said Xbox is committed to making the games available for "several more years" after Sony's Activision deal expires.

However, Sony Interactive Entertainment CEO, Jim Ryan says that Microsoft's current proposal for continuing PlayStation support is "inadequate on many levels."