Telecom regulator TRAI''s report purportedly assessing zero loss in 2G spectrum allocation during the tenure of former telecom minister A Raja on Wednesday came under sharp criticism of the Supreme Court which questioned the functioning of the autonomous body.

"We are really surprised over the communication. It was created as an autonomous regulator. It is a serious debatable issue what they have done and stated in recent days," a bench of justices GS Singhvi and AK Ganguly said while indirectly referring to the Telecom Regulatory Authority of India report.

CBI also expressed concern over the findings of TRAI and said it has not accepted the report.

"I agree that it is a matter of concern. We have not accepted the report. Anybody (accused in the scam) can take advantage of it," senior advocate KK Venugopal, appearing for the agency submitted.

The bench also said "everything should have been left to the court to decide. We have not made any observation so that nobody is prejudiced."

"We will reserve our observation on this but this has surprised us," the bench said.

The bench also expressed surprise over the difference in computation between CBI and CAG on the loss to public exchequer due to irregularities in spectrum allocation during Raja's tenure.

"CBI's estimate on loss is substantially lower than the presumptive loss given by CAG. CBI came out with a concrete figure that has been contested," the bench said.

CAG in its report has said there was a presumtive loss of Rs 1.76 lakh crore but CBI in its chargesheet calculated the loss to Rs 30,984 crore.

The bench also remarked on the use of term "alleged" with the scam.

"Some people still call alleged 2G scam," the bench said. Venugopal then replied "I call it 2G scam as the chargesheet has been filed in the case".

The court made the remarks during the hearing of Janata Party President Subramanian Swamy's plea seeking a CBI probe against home minister P Chidambaram for his alleged culpability in 2G scam.

Swamy alleged Chidambaram as the then finance minister was party to a conspiracy with Raja in deciding the price for spectrum, which was contested by CBI and the Centre.

CBI and the Centre opposed Swamy's plea saying it is beyond the Supreme Court's jurisdiction to decide as the probe into the multi-crore scam was complete and only the trial court can entertain such a petition.