Sinha who has been a staunch critic of PM Narendra Modi and his policies said “democracy is in danger.”
Speaking at the event, he said , “our future generations will criticise us if we maintain silence on the issues that are of immense concern in the nation right now.”
"I end my all ties with BJP, will not join any political party. I will fight for democracy."
It appears that Sinha may formally join forces with opposition parties as they work to put up a united front against the BJP.
According to news agency PTI, leaders from the Congress, Trinamool Congress MP Dinesh Trivedi, RJD's Tejashwi Prasad Yadav, RLD leader Jayant Choudhary, Aam Aadmi Party's Sanjay Singh and disgruntled JD(U) leader Uday Narayan Choudhary are attending the programme, Samajwadi Party spokesman Ghanshyam Tiwari told reporters in Patna. Tiwari's party would also attend the exercise.
Former MP Sharad Yadav has also been invited.
Sinha had launched 'Rashtra Manch' on January 30. He said it will be an apolitical forum and is formed to highlight "anti-people" policies of the Centre.
He had left his party red-faced in September last year by blaming demonetisation and GST for the slowing down of the economy.
Sinha’s son Jayant is a Minister of State for Civil Aviation and a BJP MP from Jharkhand’s Hazaribagh.