The Central Bureau of Investigation (CBI) on Saturday expanded its probe into the 2G spectrum allocation to cover the Vajpayee-led National Democratic Alliance regime, registering a case against Shyamal Ghosh, former Telecom Secretary, and two Telecom service providers Airtel and Vodafone for alleged irregularities.

The agency searched the offices of Bharti Airtel, Vodafone India and two former officials of the Department of Telecom in connection with the alleged irregularities.

Searches were carried out at five locations including Bharti Airtel's headquarters in Gurgaon and at Vodafone's offices in Delhi and Mumbai. Residences of Mr Shyamal Ghosh and former Deputy Director of the Department of Telecom, Mr J.R. Gupta, were also searched.

The CBI has registered a case under the Prevention of Corruption Act 1998 against all of them on charges that 2G spectrum allocation under the NDA Government may have caused a loss of Rs 508 crore to the national exchequer.

“It is alleged that the then Secretary (Telecom) and the then DDG(VAS), Department of Telecom, entered into a criminal conspiracy with the beneficiary private companies, based at Delhi and Mumbai, and abused their official positions as public servants,” the CBI said.

The investigating agency said that the two DoT officials, with approval of the then Telecom Minister late Pramod Mahajan , took an alleged hurried decision on January 31, 2001 to allocate additional spectrum beyond 6.2 MHz. Mahajan has been excluded from the investigation since he has expired.

“The accused persons also decided to allocate such additional spectrum beyond 6.2 MHz by charging spectrum fee of an incremental 1 per cent Adjusted Gross Revenue (AGR) only instead of charging incremental 1 per cent AGR on allotment of spectrum beyond 6.2 MHz and charging incremental 2 per cent AGR on allotment of spectrum beyond 8 MHz, as applicable in normal prudence,” the CBI said.

It was further alleged that the accused persons showed undue favour and caused undue cumulative advantage of approximately Rs 508.22 crore to beneficiary companies.

The case relates to additional 2G spectrum given to GSM operators between 2001 and 2007. Mobile operators were initially given 6.2 Mhz of spectrum bundled with their licence, but later on additional spectrum were given based on a subscriber linked criteria.

The Comptroller and Auditor General (CAG) in its report on the 2G spectrum scam had earlier said that the national exchequer lost Rs 36,993 crore as a result of spectrum given to incumbent players based on subscriber-linked criteria.

According to CAG, nine operators, including BSNL and Idea Cellular, had got additional spectrum. While Airtel got 32.4 Mhz of additional spectrum in 13 circles, Vodafone was given 19.6 Mhz in 7 circles.

The one-man committee, appointed by current Telecom Minister, Mr Kapil Sibal, to investigate telecom decisions since 2001 had also faulted NDA government in this regard.

Reacting to the CBI visit, a Bharti Airtel spokesperson said: “We would like to categorically state that all the spectrum allotted to us from time to time has been strictly as per the stated Government policy. We are providing all details and correspondence to the authorities and shall provide complete support as needed in the matter.”

A Vodafone spokesperson said, “All our documents are in complete compliance with the governing laws and regulations. Vodafone India is completely co-operating with the officials and will provide them all the required details as part of their checks.”

Meanwhile, the BJP termed CBI's move as a “political conspiracy” and a “last ditch attempt” to save the Home Minister, Mr P. Chidambaram, whom it alleged of being party to the 2G scam under the UPA Government.