Microsoft is set to shut down Skype’s London office, where currently around 400 people are employed, although it is yet to say when exactly this will happen.

The company said it is consolidating its London offices and moving staff to a new site.

Skype was founded in London in 2003 and acquired by Microsoft in 2011 for $8.5 billion. It has gained popularity for making voice and video calls and has around 300 million monthly active users.

Microsoft said it has “made the decision to unify some engineering positions, potentially putting at risk a number of globally focused Skype and Yammer roles”. Yammer is a private social network for enterprises.

The firm added that it is “deeply committed to doing everything we can to help those impacted through the process,” including “entering into a consultation process and offer new opportunities, where possible.”

The Financial Times quoted a former Skype employee as saying that “I know it’s natural to integrate, but Skype is a shell of the company it once was… Now, it’s a Redmond, Microsoft-led company rather than an independent Skype.”

Last month, Microsoft said it planned to cut 2,850 jobs over the next 12 months, part of which will come from Skype’s London closure. This will take the total number of redundancies worldwide to 4,700 by the end of its fiscal 2017.

The latest jobs cull is part of a sales restructuring earlier this month, following the departure of long-term COO Kevin Turner.

Microsoft is also reportedly working on an app called Skype Teams to compete with popular enterprise collaboration service Slack, following reports of a failed $8 billion bid for the company.