SP leader Mulayam Singh Yadav and MPs from TDP and Left parties on Friday sat on a dharna in front of Parliament House to seek a judicial inquiry into coal blocks allocation.

Eight parties, including the Samajwadi Party and the Left, have joined hands to protest the continued disruption of Parliament and are demanding a probe by a sitting Supreme Court judge into the coal block allocation issue.

"Our attempt is to unite non-NDA, non-UPA parties to demarcate ourselves from BJP and Congress, both of which are involved in corruption relating to mining and therefore do not want a debate in Parliament," CPI(M) leader Basudeb Acharia had said yesterday.

Acharia had said the BJP had also made similar allocation of coal blocks in Chhattisgarh and Jharkhand, apart from the mining scam in Karnataka.

Leaders of SP, CPI, CPI(M) and TDP met yesterday in the backdrop of Parliament failing to transact any business for almost two weeks, with the BJP continuing to create ruckus by pressing its demand for the resignation of the Prime Minister.