"Whether our party president is guilty or not is not the issue today. The issue is that all of us in public life should be beyond reproach...I call upon Shri Nitin Gadkari, with all the humility at my command, to immediately step down from the post of party president," he said.
Interestingly, Sinha made the demand after being with Gadkari at a 90-minute meeting of the Parliamentary Party's Executive Committee at the residence of L K Advani in the morning.
The party reacted sharply disapproving his demand, saying it "does not deem it appropriate" and appealed to him to reconsider his stand. It said various party forums were available to him for discussing the issue.
Sinha's demand brings alive once again the campaign initiated by BJP Rajya Sabha MP Ram Jethmalani and his son Mahesh for the party chief's resignation in the wake of reports of alleged dubious financing of Purti Sugar and Power Group.
The campaign against Gadkari had appeared to take a backseat after the party backed him in the wake of a clean chit given by RSS ideologue and chartered accountant S Gurumurthy, who had gone into the balance sheet and accounts of the Purti group.
But its revival may have come at an inappropriate time when the party plans to corner the government on various issues, including alleged scams, in the winter session of Parliament beginning Thursday.
Jethmalani while demanding Gadkari's resignation had claimed the backing of Yashwant Sinha, Jaswant Singh and Shatrughan Sinha. Senior leader from Karnataka Jagdish Shettigar has also demanded Gadkari's resignation.
Today, the eminent lawyer said he was happy that Sinha has openly come out in his support.
Sinha said he was issuing his statement for Gadkari's resignation with a "great deal of sadness and regret and after exhausting the forums available" for him in the party.
"I am confident that the issue I am raising has merit and I have faith in the wisdom of the party to be able to deal with this issue.
"In fact, it is this faith which kept me from issuing this statement earlier. Unfortunately, despite my best efforts the party has been unable to take a decision in the matter," he said.
Recalling that in the past too he had raised his voice against supporting Anshuman Mishra in the Rajya Sabha elections, Sinha said, "the party had heeded my advice then and I hope it does now.
"The BJP has always set the highest standard of conduct in the past which should be followed even now. We were a party with a difference earlier. We must continue to be a party with a difference even today and in future."
The former Union Minister said he has been "greatly saddened" by the events over the last few weeks.
"We have also deeply disappointed those who were looking towards us to fight the mind boggling corruption of the Congress party.
"We have no right to let down the people of India this is what we have done by taking the easy way out through a questionable method of self-certification," he said taking a dig at Gurumurthy's clean chit.
Reacting on Sinha's demand BJP Chief Spokesperson Ravi Shankar Prasad told reporters, "Sinha is a senior leader of the party and all forums of the party are available to him. The party considers the statement issued by Sinha (demanding the resignation) as inappropriate.
"The party would appeal to him to reconsider his stand."
Sinha earlier said this is the time to stand up and be counted.
"I seek nothing for myself. I have nothing left to prove in my life. But, I want that each member of the BJP should be able to hold its head high as we have always done," he said.
The MP from Hazaribagh in Jharkhand said the party should continue to serve the people with pride and honour.
"We must ensure that the country comes out of the present morass of corruption and does not sink deeper in it. Our credentials must not be questioned in this fight against
"I would also like to put this question to the workers of the party and people at large. If I am wrong, please tell me so. If I am right, please support me in whatever way you can," he said.
Sinha said the highest standard of conduct set by leaders like Shyama Prasad Mukherjee, Deen Dayal Upadhyay, Atal Behari Vajpayee and L K Advani must be adhered to at all costs.
"The nation is in peril, our democracy is threatened and our future is far from perfect. The BJP must rise to the occasion and save the country," he said.