The BJP-led Opposition yesterday demanded the resignation of Prime Minister Manmohan Singh and the scrapping of all coal mines allotted between 1993 and 2010, after a parliamentary standing committee said in its report that allocations were unauthorised, illegal and most non-transparent.

In its report, tabled in Parliament on Tuesday, the standing committee said that the government adopted the most non-transparent procedure for allocation and supply of coal blocks between 1993 and 2010.

Trinamool Congress MP Kalyan Banerjee, who chaired the committee, demanded cancellation of all coal blocks where production is yet to start, in addition to probing the role of government officials involved in the process of coal block allotment.

CPI leader Gurudas Dasgupta demanded Prime Minister Manmohan Singh to resign, saying he should hold responsibility for the scam as he held coal portfolio for most of the time when the allocations were made.

Demanding Mr. Sing's resignation, Dasgupta said, "The Prime Minister is guilty of dereliction of duty on a number of counts."

But, UPA dismissed the Opposition's demand for Mr. Sing's resignation curtly. "Let them ask" was Congress President Sonia Gandhi's abrupt response when reporters sought her comments on the Opposition's demand.