The UK competition watchdog has officially approved BT's £12.5 billion buy out of mobile phone firm EE.
Authorisation from the Competition and Markets Authority (CMA) means the deal brings together the UK's largest fixed and mobile telecoms businesses.
It comes after the merger was provisionally given the green light in October last year.
Telecoms giant BT announced in February last year that it had agreed to acquire the firm.
EE is jointly owned by France's Orange and Deutsche Telekom, both of which will be shareholders in BT following the deal.
Rivals have claimed the move would allow BT to "remonopolise" the UK telecoms sector, forcing broadband firms to use its old network.
But John Wotton, who chaired the inquiry into the deal, said evidence "does not show that this merger is likely to cause significant harm to competition or the interests of consumers".
BT chief executive Gavin Patterson described the acquisition as "great news".
"We are pleased the CMA have found there to be no significant lessening of competition following an in-depth investigation lasting more than 10 months," Mr Patterson said.
"The combined BT and EE will be a digital champion for the UK, providing high levels of investment and driving innovation in a highly competitive market," he added.
Following today's approval, BT will commence the formal process of completing the deal.
A prospectus will be issued in the week commencing January 25 with the deal set to close on January 29 when Deutsche Telekom and Orange will receive shares in BT.
The UK telecoms giant will post its third-quarter results on February 1.
The deal is expected to be completed before the end of March.
