Mobile networks have been left outraged at Ofcom's decision to increase the fees that they should pay for mobile spectrum that they have acquired.
The communications regulator published a consultation on revising annual licence fees for the 900 MHz and 1800 MHz spectrum bands which cover voice calls, 3G and some 4G services.
Ofcom said it was directed by the government in December 2010 to revise the fees so that they reflect the "full market value".
The current proposed total annual licence fees for the spectrum bands in question have risen from £15.6m to £83.1m for both Vodafone and O2, £24.9m to £107.1m for EE, and £8.3m to £35.7m for Three UK.
Overall, it believes that the 900MHz band should increase from £24.8m to £138.5m and that the 1800MHz band should be bumped up from £39.7m to £170.4m.
A Vodafone spokesperson said that the company was "disappointed that Ofcom is proposing a 430 per cent increase in the fees we pay for our existing spectrum at a time when we are investing more than ever in vital national digital infrastructure".
The spokesperson added that the regulator "should be encouraging" private sector investment in infrastructure and new services like 4G.
EE took a similar stance to its rival, with a spokesperson for the UK's biggest mobile network claiming that the proposed increase in licence fees is "excessive" at a time when it claims to be investing heavily in the rollout of 4G.
A spokesperson for the smallest network that will offer 4G services - Three UK - said that the proposals "fail to recognise the relative value of high and low frequency spectrum, despite evidence from around the world".
"The sums proposed by Ofcom over-value high frequency spectrum," the spokesperson suggested.
But while the other networks were criticising the planned price rises, O2 said that the consultation document was "expected and the approach appears to be in line with Ofcom's earlier guidance".
All of the operators suggested that they would challenge the decision as part of the consultation, which is due to close on 19 December 2013.
In the past few years, mobile spectrum has been at the centre of several battles between mobile operators, as well as regulator Ofcom.
The 4G spectrum auction, which was completed earlier this year, raised £2.34bn, over £1bn less than the Office for Budget for Responsibility (OBR) had forecast. It is unclear whether Ofcom is trying to make up the shortfall by increasing the prices of the spectrum, but this would be unlikely as the deficit is the subject of an ongoing investigation by the National Audit Office.