Vodafone (VOD.L) and CK Hutchison (0001. HK) unveiled the long-awaited 15 billion pound ($19 billion) merger of their British mobile operations on Wednesday, saying the creation of a new market leader would help drive competition and investment.

Expected since the two companies disclosed talks in October, the deal faces prolonged scrutiny by the anti-trust regulator into whether having a single operator with 27 million customers could lead to higher mobile prices.

Seeking to win over politicians, unions, and the competition authorities, the two groups said they would invest 11 billion pounds to create “one of Europe’s most advanced standalone 5G networks”.

The long-awaited 15 billion pound ($19 billion) merger of Vodafone (VOD.L) and CK Hutchison (0001. HK)’s British mobile businesses was announced on Wednesday, with the companies claiming the emergence of a new market leader will encourage competition and investment.

The transaction has been anticipated since the two businesses announced their discussions in October, but the anti-trust agency will continue to closely monitor it to see if having a single operator with 27 million subscribers will result in higher mobile costs.

The two organizations claimed that they will invest 11 billion pounds to build “one of Europe’s most advanced standalone 5G networks” in an effort to get the support of lawmakers, unions, and competition regulators.

A joint venture between Telefonica (TEF.MC) and Liberty Global (LBTYA.O), the merged provider will surpass BT’s (BT.L) EE and VM O2.

If it accepts, Vodafone, the third-largest mobile operator in Britain, will have the option to purchase the Hong Kong-based company three years after the deal is finalized.