Taking serious exception to Prime Minister Manmohan Singh [Images] giving a clean chit to former External Affairs Minister K Natwar Singh in Iraq's controversial oil pay-offs, the Bharatiya Janata Party said on Wednesday that it had put a question mark on the rationale behind institution of a judicial probe into the issue.

"The way Dr Singh shielded Natwar Singh at a press conference in Patna shows he is taking the Volcker panel report on controversial oil pay-offs lightly. His giving a clean chit to Natwar has put a question mark on the very rationale behind the judicial probe ordered by the United Progressive Alliance government," BJP general secretary Arun Jaitley told reporters.

Charging Dr Singh with trying to portray the former External Affairs minister as 'innocent', he said, "While remaining Mr Clean himself, Dr Singh has developed the habit of giving clean chits to his tainted ministers. He gave clean chits to Lalu Prasad, Shibu Soren and Jaiprakash Narain Yadav before Natwar Singh."

Singh had, on Tuesday, dubbed the Volcker findings as 'unsubtantiated' references and said setting up of the judicial inquiry and the fact-finding mission is a 'search' for truth.