The two broadband providers wrote a joint letter to the UK regulator.
BT and Virgin Media have written a joint letter to Ofcom asking the regulator to abandon plans to open up high-speed broadband networks to rivals.
The Financial Times reports that the two parties argued any attempt to allow smaller rivals to access networks would decrease investment and raise prices for consumers, claiming that the "significant regulatory uncertainty" would "undermin(e) the return on sunk investments and therefore disincentivis(e) future infrastructure investments."
The unlikely pair claimed to be "very concerned" by calls for regulation, adding that "allowing multiple operators to tamper with the physical network will cause service faults for customers".
The letter implored Ofcom not to abandon its current approach, arguing that "effective and growing competition in retail business connectivity markets, where there is little remaining regulation required".
BT has often been accused of holding a monopoly in the UK due to its huge assets and dominant market position. With its acquisition of EE, it will now also control what is currently the UK’s largest mobile offer and already has plans to launch a low-cost mobile offering to existing customers.
This latest clash between BT and the regulator comes a day before the implementation of new rules from Ofcom, which will require BT to maintain a margin between wholesale and retail superfast broadband charges.