Government on Tuesday filed an affidavit in the supreme court rejecting the allegation of interference by law minister Salman Khurshid in the investigation into 2G spectrum case as "baseless" and said it was not trying to "influence" the probe against Essar Group.

In the affidavit, the centre said such allegations were being made to tarnish and discredit government's image and such a serious charge against the minister who is not a party to the matter was "impermissible" in law.

The centre filed a comprehensive affidavit in response to the notices that the probe agencies were allegedly going soft on companies like Essar, Loop and their promoters by not slapping corruption charges against them in the case arising out of the 2G spectrum scam.

The court had sought response on an application filed by an NGO, centre for Public Interest Litigation (CPIL), which also alleged that such a decision was "facilitated" by the intervention of CBI Director and law minister Salman Khurshid.

Brushing aside the allegations, the centre's affidavit filed through advocate Wasim Ahmed Qadri, said "it is emphatically denied that the law minister is publicly giving clean chit to Essar/Loop. The entire matter is in the domain of the CBI and the court, which will take an independent view of all aspects of the matter."

It said that making "such serious allegations" against Khurshid and others, who are not a party to the case is "impermissible" in law and the application filed by the NGO centre for Public Interest Litigation (CPIL) are liable to be rejected.

The affidavit said "petitioners have made it a practice to make serious allegations against the functionaries of the government holding high constitutional positions, one after another".

The affidavit said the allegations "shows a design to tarnish their image and discredit the government, taking undue advantage of the wide publicity given to court proceedings including the baseless allegations made in such interim applications (IAs)".

Denying the allegation that Khurshid was publicly giving clean chit to Essar, the affidavit said the opinion of the Attorney General (AG) G E Vahanvati did not intend to interfere in the probe.

"This (AG's) opinion did not and was never intended to interfere with the investigation being done by the CBI. The applicants' plea that interference of an influential minister is evident, is baseless," the centre said.

"CPIL is consistently opposed to the ruling party and have been adopting the devise of filing IAs ostensibly seeking permission to bring certain facts on record but in the applications or the affidavits filed in support thereof targeting individual ministers or the Attorney General or officers of CBI by name behind their back in flagrant breach of principles of natural justice.

The centre said "a proceeding which started as public interest litigation is now turning out to be a political interest litigation".

The affidavit said all aspects were considered by the departments of Telecom and Company Affairs before granting approvals relating to acquisition of shares.

The centre said it was for the investigating agency to consider all relevant facts and materials including those mentioned in the AG's opinion and take necessary steps and the NGO cannot assume a role of supervisors of the probe.

The affidavit said "It is respectfully submitted that the applicants cannot assume the role of self-appointed supervisors of investigation on the basis of their own suspicion and presumption that everyone is corrupt.

"No department of the government can interfere with the ongoing investigation of the CBI or the ED much less the applicants (NGO) who are private parties and have no role at all in this matter."

The ministry sought rejection of the interim application filed by the NGO saying it was not maintainable after orders have been reserved on conclusion of elaborate arguments by all the parties in the main matter.

It said the apex court's judgement is still awaited on the issue whether court monitoring can continue after the trial court has taken cognisance of the offences involved and by filing this application, the NGO have "prejudged" the issue and assumed that monitoring will continue.