Global firm Linklaters has advised CK Hutchison Holdings Limited and the Three UK Group on the merger of Three UK and Vodafone UK.
The deal will combine the respective telecommunications operations to create the largest mobile operator in Britain.
The combined group will be owned 51% by Vodafone and 49% by Hutchison.
The combined company will be able to invest significantly in Britain to create a comprehensive 5G network, addressing exponential traffic growth.
Through combining its standalone 5G network with best-in-class spectrum, the merged business will be better positioned to enable advanced 5G-based innovations, Linklaters has said.