He also asserted that Congress President Rahul Gandhi is the party's obvious choice as prime ministerial candidate in the Lok Sabha polls, but any announcement would have to wait for the outcome of alliance talks among opposition parties.

And he believed United Progressive Alliance (UPA) chairperson Sonia Gandhi is the best person to bring together like-minded opposition parties against the ruling Bharatiya Janata Party (BJP)-led NDA.

"As far as I am concerned and our party is concerned, the choice is obvious. But till such time, in case there is a larger collaboration and alliance, courtesy demands that we wait till that announcement is made by the alliance. But for us it is very clear. Rahul Gandhi is very clearly the person for the job and who would lead from the front," Khurshid told IANS in an interview.

He was asked if there should be a declared opposition candidate against Prime Minister Narendra Modi in the 2019 general election.

The former Union minister, whose latest book "Triple Talaq: Examining Faith" has hit the stands, said there has been severe erosion in Modi's credibility.

"I think there is severe erosion taking place as far as Mr Modi's credibility is concerned, but I won't say that the erosion is adequate yet. There is a slide, and erosion continues," he said.

Asked about the possibility of an opposition alliance coming about against the NDA, he said: "It is difficult to say right now, but if an alliance does not happen, we will all be very sorry for losing an opportunity."

He said discussions were quietly taking place at various levels. "There is a realisation in all parties that it is a very important turning point for Indian history. I think the ego barriers of the past do not exist any more. But it still requires a lot of footwork. Somebody quietly has to take that initiative. I can't say who will finally be the person who will do it.