Suspended Congress leader Natwar Singh's plan to corner the government on the leakage of Pathak Authority report through a breach of privilege motion against Prime Minister Manmohan Singh fell flat in the Rajya Sabha on Thursday with the chairman rejecting it.

However, he felt the leakage of the contents of the report that went into the Iraqi oil contracts scam was a "serious matter" that should be investigated.

"Past precedents in similar cases also lead me to reach the decision that this matter does not constitute any breach of privilege of the House," Bhairon Singh Shekawat ruled in the House as it met post-lunch after two adjournments.

"The said notice is not admissible," the chairman said in his much-awaited ruling. Natwar Singh was not present when it was delivered.