The £31 billion merger deal between Liberty Global’s Virgin Media and Telefonica’s O2 has received the final approval from the Competition and Markets Authority (CMA).

The deal to create a 50-50 joint venture brings together O2’s 36.6 million customers on its mobile networks with Virgin’s 5.7 million cable users and 3.4 million mobile subscribers.

O2, which also provides the MVNO network for GiffGaff, Tesco Mobile and Sky Mobile, is the UK’s largest phone company.

The deal will see all 12,000 Virgin Media employees and 6,500 O2 staff in the UK work under the same umbrella company.

The CMA was initially concerned that, following the merger, Virgin and O2 could raise prices or reduce the quality of their wholesale services.

The tie-up will create a major rival to BT by bringing together different platforms. The transaction is now expected to close on June 1, 2021. The CMA provisionally authorized the transaction last month, with no recourse required, after the Commission Europe to forward it to the CMA.

The venture is expected to produce synergies valued at £6.2 billion based on net present value after integration costs and will create a nationwide integrated communications provider with £11 billion in revenue.

Liberty Global and Telefonica announced last month the appointment of Lutz Schuler as Chief Executive Officer and Patricia Cobian as Chief Financial Officer of the combined company. Schuler is currently CEO of Virgin Media and Cobian, Chief Financial Officer of O2.

“This is a watershed moment in the history of telecommunications in the United Kingdom as we are now authorized to present a real alternative where it has not been existed before, as we invest in fiber and 5G, something the UK needs to thrive,” Jose Maria Alvarez-Pallete, Chairman of Telefonica and Mike Fries, CEO of Liberty Global, said.