Kolkata,  Former Union minister Yashwant Sinha has asked for an immediate, high-level and independent enquiry into the 'audio clip' released by the BJP IT cell claiming it contained a phone conversation between West Bengal Chief Minister Mamata Banerjee and a party candidate.

Sinha, who recently joined the Trinamool Congress, told IANS in an exclusive interview that the union government has "very strict rules" on authorisation of wire tapping and eavesdropping on telephone conversations.

"There is a clear list of categories whose phones can be tapped for reasons of national security -- terrorists, smugglers, suspected foreign espionage agents and the like," said Sinha. "I can say with the authority of experience that phones of Chief Ministers cannot be tapped."

He insisted that tapping phones of Opposition leaders without authorisation should not only merit stringent legal action but was tantamount to denial of privacy and political rights in what is still a democracy.

The audio clip has a female voice which claims to be Mamata Banerjee and the male voice on the other side is claimed to be that of TMC's Sitalkuchi MLA candidate Partha Pratim Roy.

It claims that Mamata Banerjee is asking Partha Pratim Roy about those killed in the Sitalkuchi firings during the fourth round of West Bengal assembly polls. "Keep the dead bodies so that the party could hold a rally with the dead," the female voice is heard saying.

Sinha told IANS only national security agencies have the wherewithal to wire-tap phones and eavesdrop on telephone conversation.

"We need an enquiry where these agency heads must be summoned to depose about whether they have been tapping a sitting chief minister's phone and if so, who has authorised the tapping," Sinha said.

If it is found they did not do it and the audio clip is fake, the BJP has a huge explanation to make, said Sinha.

"How can the BJP release a fake audio a day before the polls! Is it not an effort to unfairly influence the elections! Will the Election Commission take cognisance of it?" Sinha told IANS.

The veteran former BJP leader, now in Trinamool Congress, said the BJP is now caught between the "rock and the hard place."

"If the audio clip is genuine, it is obvious the central agencies are behind the wiretap. If that is true, how is it possible they are releasing the material to the IT cell of the ruling party. Also the question of who authorised the wiretap as the Intelligence Bureau is under the Home Ministry," said Sinha, adding the Home Minister Amit Shah has to come clean on the issue.

"If the audio tape is fake as Partha Pratim Roy has already denied any such conversation took place, Mamata Banerjee can sue the BJP IT cell chief Amit Malviya for criminal defamation and the Election Commission will have to take cognisance of its illegal activities," Sinha said.

"The activity of the BJP IT Cell reminds of Goebbels propaganda department in Nazi Germany. The country should know where it is heading," Sinha told IANS.

BJP leaders are accusing Mamata Banerjee of "playing politics over dead bodies."

Bengal BJP leader and sitting MLA Samik Bhattacharya latched on the part of the audio clip where the lady is saying "SP, IC, Commandant... could be transferred." "That shows the condition of law and order in West Bengal," he told mediapersons.

But Trinamool Congress Rajya Sabha MP Sukhendu Sekhar Ray warned the BJP of 'walking into a pit.'

"Does the BJP IT Cell chief realise his action points to telephone surveillance of a Chief Minister! The Home Minister has categorically claimed in parliament, I repeat Parliament, that no Chief Minister is under telephone surveillance," Ray told mediapersons.

"We will expose these lies politically," he said.

The BJP IT cell before a previous round of Bengal polls had released select portions of a conversation between Mamata Banerjee's leading political strategist Prashant Kishor and some journalists, claiming even he had acknowledged the BJP was headed to win the state polls.

Kishor dared the BJP IT Cell to release the whole interview and denied predicting a BJP win. He stuck to his previous prediction that the BJP's tally 'will not cross double digits'.