Telcos are calling on Ofcom to slap a 30 per cent cap on operators bidding in the next spectrum auction - a move that would limit the proportion of airwaves an operator can own.
TalkTalk, Three, CityFibre, the Federation of Communication Services, and Relish called on the regulator to impose the moratorium in a joint letter seen by The Register.
Three has previously argued for a 30 per cent cap - arguing that EE owned by BT, has 42 per cent of the spectrum currently available, while Vodafone has 29 per cent and O2 and Three have 14 per cent and 15 per cent respectively.
Next year Ofcom will auction another tranche of a critical but finite national asset with the release of 190MHz of spectrum. The regulator is expected to open its spectrum consultation in the next month.
The letter to Ofcom head Sharon White said spectrum is the "lifeblood" of the mobile industry.
"The UK suffers from the largest imbalance in spectrum distribution across mobile operators of any developed country. BT already owns nearly half of the UK’s vital airwaves and Vodafone nearly a third," it said.
"This imbalance has developed as a consequence of Ofcom’s failure to put protections in place that ensure all networks have access to sufficient amounts of spectrum to deliver both a great mobile service and competitive prices."
Earlier this year the EU, backed by Ofcom, slapped down the proposed £10.5bn merger between O2 and Three, arguing that such a move would have a negative impact on consumers.
The letter added: "Ofcom has acknowledged the role that four networks with sufficient access to spectrum played in mobile prices falling by two thirds between 2003 and 2013."
It added: "The next auction of spectrum could be your last opportunity to give UK mobile customers a highly competitive mobile market which gives them the speeds, coverage and performance they deserve and demand.
"We call on Ofcom to apply a cap of 30 per cent on the total amount of mobile spectrum any one company can own following the auction." This would presumably entail an enforced sell-off by some of the current stakeholders.
The Register has contacted Vodafone and BT for comment. ®