Since then, former National Security Advisor Brajesh Mishra and another former cabinet minister Yashwant Sinha have backed Jaswant Singh over the hijacking episode, putting pressure on Advani to give his version of what happened in 1999.

But the BJP source said that Advani would keep quiet despite all the criticism about him.

'We have been asking him to tell his story but he is not interested,' the source said. 'He wants to play by the rule book. He says if he starts leaking information, others will do the same.'

'In any case, he knows who is keeping the media informed,' he said. 'But he doesn't want to do what they are doing.'

There is growing speculation in the BJP that Advani, one of the best known leaders of the party, will step down, probably later this year, as leader of the opposition in the Lok Sabha.

At the same time, BJP president Rajnath Singh is also expected to quit his post, leading to major changes in the leadership of the main opposition party.