Comptroller and Auditor General (CAG) Vinod Rai on Monday defended the estimate that the spectrum allocation under A Raja caused the exchequer a loss of Rs 170,000 crore in face of arguments of UPA members of Parliaments Public Account Committee that the finding was presumptive and based on hindsight.

According to sources, Congress members Ashwini Kumar and K S Rao along with DMKs T Shiva raised doubts about the findings of the PAC an estimate that led Congress leadership to oust Raja as the telecom minister and intensified the political tussle with the opposition.

The meeting held against the background of Prime Minister Manmohan Singhs offer to appear before the panel fully reflected the government - opposition divide as the members belonging to the latter asked the CAG to elaborate on the key aspects of its damning report on the spectrum scam.

Former finance minister Yashwant Sinha urged Rai to explain who could have been responsible for the change in the terms and reference of the Group of Ministers on telecom which allowed Raja to play the sole arbiter of spectrum pricing.

According to sources, Sinha stressed that it is the PM who sets up a Group of Ministers, while its terms and reference are settled by the cabinet secretary , to argue that the Department of Telecom itself could not have brought about the change, which eliminated any role for the finance ministry in spectrum pricing.

Defending his estimate, Rai is learnt to have forcefully argued that the criticism does not hold because an audit by very definition is a post-facto examination of accounts. He also stated that all estimates of CAG or revenue losses are presumptive and yet they have so far been accepted by the government.

Sinha and other opposition members asked the Rai to explain the disconnect between Rajas claim that he followed the firstcome first-served policy , and CAGs finding that he didnt . The former finance minister, according to sources, also asked the CAG to shed light on former telecom secretary D S Mathurs recusal from decisions on spectrum licenses as well as that of the then financial adviser to take voluntary retirement because of the pressure brought to bear upon him.

Though CAG cannot be summoned as a witness, members stressed that Rai was there as their friend, philosopher and guide.