Mr Singh confirmed that Mr Shah would succeed him after a meeting of the BJP's top decision-makers, called the parliamentary board, which met this morning to firm up the party's parliamentary strategy for the five-week Budget session that began on Monday.
Mr Shah had some weeks ago emerged the front-runner vis-a-vis colleagues such as JP Nadda and Om Prakash Mathur, with assembly elections due in Maharashtra, Haryana and Jharkhand. In the national elections in May this year, Mr Shah, 50, engineered a massive victory for the BJP in Uttar Pradesh, India's largest state, delivering 71 of the state's 80 parliamentary seats. (How Amit Shah Delivered Uttar Pradesh For the BJP)
The party hopes he will do that again in the forthcoming assembly elections, crucial for the BJP to improve its numbers in the Rajya Sabha, where it is in a minority.
When Mr Modi was Chief Minister of Gujarat, Mr Shah served as his Home Minister, but had to resign in 2010 after he was alleged to have sanctioned a fake encounter by the state police, which saw three Muslims being killed by officers who alleged they were terrorists planning to assassinate Mr Modi. (Gujarat minister Amit Shah resigns, Modi says Shah is not guilty)
Mr Shah faces murder charges for allegedly allowing the extra-judicial killing of Sohrabuddin Sheikh, a small-time criminal, his wife and a witness.
During the campaign for the national election, Mr Shah was banned by the powerful Election Commission from rallies and speeches after it found him guilty of delivering "hate speeches" designed to promote "hatred and ill will" between religions. (Amit Shah gets Election Commission notice for hate speeches in UP)
The ban was lifted after Mr Shah vowed in writing that he would not "use abusive or derogatory language in the campaign".
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