The criminal defamation case against Singh was filed by BJP President.
"Now, I can say everything in front of the court the way Mr Gadkari has worked as a businessman and how he has links with various other businessmen, which all companies of his were fake and how he earned profits," he said.
Earlier, Singh accused Gadkari of pocketing huge sum to the tune of Rs 490 crore in the coal block allocation to businessman and party MP Ajay Sancheti.
Singh appeared before Metropolitan Magistrate Sudesh Kumar in pursuance to the summons issued against him by the court on Nov 17 and the judge granted bail to him on a personal bond of Rs 50,000 and a surety of the same amount.
The court, after finding "prima facie" evidence against Singh, had directed him to appear before it to face trial for the offence punishable under section 499 (defamation) and 500 (punishment for defamation) of the Indian Penal Code (IPC).
(With inputs from PTI)