In October, Ofcom will invite mobile providers to bid for a share of the UK’s usable radio spectrum.
In an attempt to better support 4G and 5G, the watchdog is increasing the amount of spectrum up for grabs.
But it won’t be a free-for-all; Ofcom has announced that it will restrict how much any single network can buy.
The limit is designed to safeguard competition in the market, but Three says it doesn’t go far enough.
When BT and EE merged in 2016, their share of the network hit 42 per cent. It’s set to fall to 39 per cent after the auction.
By 2020, Ofcom wants it to be limited to 37 per cent, but Three, which has 14 per cent of the spectrum, contends that no network should be able to control more than 30 per cent.
Dave Dyson, chief executive of Three UK, said in a statement: “By making decisions that increase the dominance of the largest operators, Ofcom is damaging competition, restricting choice and pushing prices up for the very consumers that it is meant to protect.
“The mobile market is imbalanced and failing customers. Ofcom has shown little interest in tackling the problem. We will consider our response as a matter of urgency.”
A spokesman for Ofcom told the BBC: “We take all our decisions in the interests of consumers. This auction will keep the airwaves fair by reducing the share held by the largest operator. It will include strong safeguards to maintain a healthy four-player market and allow mobile operators to acquire the airwaves they need to compete.”