3UK-led MakeTheAirFair campaign wants Ofcom to limit operators’ frequency holdings to 30%.

A campaign led by 3UK and TalkTalk to impose a 30% cap on the amount of mobile spectrum that any single operator can hold has garnered support from more than 100,000 U.K. consumers, it emerged on Tuesday.

MakeTheAirFair is also backed by altnet CityFibre, the Federation of Communication Services (FCS), enterprise telco Gamma, and fixed-wireless provider Relish. The group are pressuring telco regulator Ofcom to place stricter limits on spectrum ownership.

As it stands, Ofcom has proposed restricting the amount of ‘immediately usable’ spectrum that any single operator can own to 255 MHz. For BT and its EE arm, which currently hold a combined 45% of the U.K.’s available mobile spectrum, this means they would not be able to bid in the upcoming 2.3-GHz auction. Following the 2.3-GHz auction, BT and EE’s combined spectrum share will fall to 42% – provided all the spectrum is sold off.

In addition, there are no such restrictions proposed for Ofcom’s planned 3.4-GHz auction on the grounds that it is not yet clear what sort of services it will be used for, therefore the watchdog wants to avoid potentially constraining innovation by limiting operators’ spectrum holdings.

That is not good enough for MakeTheAirFair and its 100,000 supporters though.

"The fact that so many members of the public have joined the MakeTheAirFair campaign and responded to Ofcom’s consultation shows that consumers are concerned about the massive imbalance in ownership of the nation’s airwaves," said 3UK CEO Dave Dyson, in a statement on Tuesday.

This imbalance harms competition, which could lead to higher prices, he warned.

"Our research, conducted in partnership with YouGov, has shown that over 60% of U.K. consumers fear that reduced competition between service providers will lead to increased prices. Ofcom needs to act on these concerns," Dyson said.