PARIS (AP) — Deutsche Telekom AG and France Telecom SA say they have completed the merger of their British mobile phone units to create the country’s biggest operator and shake up an intensely competitive market.

France Telecom, owner of Orange UK, and Deutsche Telekom, owner of T-Mobile, announced the proposed combination in September.

The new company will be led by the former head of Orange UK, Tom Alexander, the companies said Thursday.

The 50-50 joint venture would have about 28 million customers, making it the largest player in the U.K. with a 37 percent market share.

In February, Britain’s Office of Fair Trading said it was seeking permission from the European Commission to examine the venture’s impact in the U.K., and perhaps refer it for a full-scale investigation by the Competition Commission.