The UK Treasury may owe the mobile industry up to £300 million after a court upheld an operator challenge to a government-mandated licence fee rise, Financial Times (FT) reported.

In 2015, regulator Ofcom was asked to increase spectrum fees, which trebled the annual licence fee of many operators and resulted in the industry having to cough up £200 million a year for licences.

UK operators sought a judicial review, stating Ofcom had wrongly calculated the amounts, for instance by not taking into account network running costs.

The Court of Appeal upheld the challenge based on European Commission laws on infrastructure investment.

As a result, the treasury may now have to return the extra fees paid by operators, which are calculated to be in the region of £200 million and £300 million, although the ruling could be appealed in the Supreme Court.

The FT report quoted an Ofcom representative as saying: “This case raised an important point of law concerning the government’s spectrum direction to Ofcom. We are considering the judgement carefully,”

EE, which was very vocal about its concerns around the issue, said: “We’re happy with the outcome as we’ve always supported the view that the trebling of spectrum fees was excessive and would harm network investment. With this judgment we can continue to invest in those network improvements that really make a difference to consumers and businesses across the UK.”

News of the appeal court decision emerged as the UK government released details of fresh funding for key technology developments including 5G and artificial intelligence (AI).

In an autumn budget statement, the government announced it would spend £160 million on 5G mobile networks and £75 million on AI, while also announcing plans to put driverless cars on roads by 2021.