The UK's Competition and Markets Authority (CMA) has expressed concerns that the proposed £14.45bn merger between Vodafone and Three UK could lead to increased mobile bills for millions of customers and reduce competition in the market by diminishing the number of network operators from four to three. While the CMA acknowledges potential benefits such as improved network quality and 5G deployment, it remains skeptical of the companies' claims regarding cost stability. Vodafone and Three argue that the merger will enhance competition and investment, asserting it is essential for fixing the UK's 'dysfunctional' mobile market. They plan to collaborate with the CMA to address concerns and secure approval ahead of a final decision due by December 7. The CMA has suggested possible remedies, including commitments to network investments and protections for consumers, while maintaining the option to block the merger if necessary. The potential impact on Mobile Virtual Network Operators (MVNOs) is also a point of contention, with the CMA warning that they may face challenges in securing competitive terms post-merger.