PATNA, April 3 -- Bihar Chief Minister Nitish Kumar will resign after taking oath as a Rajya Sabha member, which is scheduled for April 10, said a senior JD(U) leader. Amid growing speculation about his successor from the BJP, the JD(U) leader said that Kumar would resign within a couple of days after returning from Delhi and the process for forming the new government would commence thereafter. "He will take the oath as a member of the Rajya Sabha and after returning, he will tender his resignation from the post of CM. He has already resigned from the Bihar Legislative Council and got elected to the Rajya Sabha. So, it is just a matter of time for him to resign from the CM's post to set the stage for the next government formation," he added. The formation of the new government is likely to happen mid-April. "Once he resigns the process for the new government formation will get underway. He will go to Delhi on April 9 and is expected to return on April 11. Nitish Kumar is clear in his mind about what he has to do and he is fully at ease," he added, refusing to elaborate on Kumar's likely successor. For Nitish Kumar, his new innings in the Rajya Sabha will also coincide with his fourth stint as the JD(U) national president. He was elected unopposed last month. Later this month, the party's national executive will also meet in Patna, in which Nitish Kumar will share the future course of the party. That will also be significant for his son Nishant Kumar, who is waiting for an active role in the party. As Nitish Kumar prepares to step down to make his debut in the Rajya Sabha-the only House he did not represent in his long career-it will give the BJP, the largest party in the state Assembly, the opportunity to have its CM in Bihar for the first time. "It will also be a test for the party, as filling the void left by Nitish Kumar will not be easy and it will be under constant scrutiny. Nitish Kumar did a lot for Bihar, but his long tenure also had the cushion of the RJD's misrule. The comparison with the RJD always made the JD(U) look much taller. The BJP CM's performance will be compared with Nitish Kumar from day one, and that will be a big boot to fill," said social analyst Prof NK Choudhary. Regarding Nitish Kumar's successor, no clear name has emerged so far, though there are wide-ranging speculations on different names....