BT has been given the go-ahead to complete its £12.5 billion purchase of EE by competition regulators.
The two companies agreed a deal in February, but it was subject to regulatory approval. Now, the Competition and Markets Authority (CMA) has said that BT's takeover is "not expected to result in a substantial lessening of competition in any market in the UK".
The regulator highlighted that BT and EE operate in largely different areas, "with BT strong in supplying fixed communications services (voice, broadband and pay TV), EE strong in supplying mobile communications services, and limited overlap between them in both categories of service".
The takeover will see BT more than treble the number of customers it has. It already has 10 million retail customers, but with EE's mobile customers the total will be taken to nearly 35 million.
John Wotton, chair of the CMA inquiry said: "Having considered all the evidence, the group does not provisionally believe that, in a dynamic and evolving sector, it is more likely than not that BT/EE will be able to use its position to damage competition or the interests of consumers."
BT chief executive Gavin Patterson said: "The combined BT and EE will be good for the UK, providing investment and ensuring consumers and businesses can benefit from further innovation in a highly competitive market".