Reserve Bank Governor Urjit Patel on Wednesday would not have escaped possible grilling by a parliamentary committee over the issue, had former Prime Minister Manmohan Singh not intervened.

Patel, who along with other RBI and finance ministry officials appeared before the Parliamentary Standing Committee on Finance, had to face some tough questions by members, sources in the committee said.

He could not reply to questions on when normalcy would return to the banking system and the quantum of demonetised currency deposited during the 50-day window.

Before the grilling could intensify, Singh, who had made a forceful speech against in the Rajya Sabha calling it a "monumental failure and organised loot", intervened to say that the central bank and the Governor's position as an institution should be respected.

He should not be made to respond to odd questions, Singh, who himself was RBI Governor once, is believed to have told the Committee.

The former Prime Minister is understood to have told Patel that he need not answer a question put by one of the members relating to non-removal of cash withdrawal restrictions.