Communications watchdog Ofcom has ruled that BT/EE will not be allowed to participate in one of its upcoming auctions for mobile broadband airwaves.
The regulator has set out its rules for next year's auction of 190 MHz of spectrum in the 2.3 GHz and 3.4 GHz bands - representing more than three-quarters of the 4G airwaves that were released in 2013. The auction was supposed to kick off last year, but was delayed by the proposed merger of O2 and Three, which was eventually blocked by the European Commission.
Ofcom will sell 40 MHz of spectrum in the 2.3 GHz band, and 150 MHz of spectrum in the 3.4 GHz band.
The 2.3 GHz band is already supported by mobiles such as the iPhone, and the airwaves "could be used immediately after release to provide extra capacity, meaning faster downloads and internet browsing for consumers".
As BT/EE - the two companies merged at the beginning of this year - already holds 45 per cent of immediately useable UK mobile spectrum, it has been banned from bidding for more. Ofcom said this was because if BT/EE were to buy all the 2.3 GHz being awarded "it would have almost half of the immediately usable spectrum in the market".
Ofcom's decision follows a request from Three that the regulator limit the amount of spectrum companies can buy up.
"People and business increasingly depend on reliable, high-speed mobile broadband. More than seven in ten adults currently have a smartphone, and the amount of data carried over UK mobile networks is rising exponentially," Ofcom said.
"Acquiring extra spectrum is one of the ways operators can increase their network capacity, and the frequencies being sold will help meet consumer demand for mobile broadband services."
The 3.4 GHz band is not currently used by most mobile devices, but is likely to be usable by future devices - Ofcom said this band has been "identified as central to the rollout of 5G across Europe".
"We are not proposing a cap on the amount of 3.4 GHz spectrum. This is because the band is not immediately useable, and we believe it is important that operators are given an opportunity to acquire this spectrum so they are able to consider early development of 5G services," said the watchdog.