The Government was "casual with taxpayers' assets" in its sale of the 4G mobile phone spectrum a Labour spokeswoman has said.
Helen Goodman accused Communications Minister Ed Vaizey of failing to make sure the expected revenues were raised after the sale brought in £1bn less than expected.
The Labour spokeswoman highlighted the announcement of a review by the National Audit Office (NAO) into the sale.
She said: "I'm sure you will join me in welcoming the NAO inquiry into why the 4G auction raised £1 billion less than forecast. It's quite wrong that in a time of austerity the mobile phone companies were given spectrum at prices below even what they were prepared to pay.
"In his letter to me, the controller and auditor general says this was different from the earlier auction of 3G spectrum where the generation of proceeds was at least one of the objectives of the auction. Why were you so casual with taxpayers' assets?"
But Mr Vaizey insisted it had been run properly and would ensure customers had access to the new, faster services much more quickly than when the previous generation of technology was sold.
He said: "I utterly reject that accusation. After the 3G auction there was an NAO inquiry, it is entirely standard procedure to have the NAO run the ruler over this auction.
"I happen to believe Ofcom did a fantastic job in running this auction, I went personally last night to congratulate the 92 men and women who worked on that auction who have delivered a fantastic result.
"The 3G auction, the companies paid far too much and it took too long to roll out 3G. Now we are likely to get 4G by the end of 2015, two years ahead of schedule, with 98 per cent coverage."