Singh had recently announced that he will relinquish his BJP role in keeping with the party's “one-man, one-post” principle.
“Shah is full of imaginative ideas and is good at organisational skills. As in charge of UP during Lok Sabha polls, he got a roaring success. BJP had never been so successful in its history in UP,” Singh said.
He also credited former Prime Minister Atal Bihari Vajpayee and Advani for making the Indian polity from unipolar to bipolar.
Singh said under Modi's leadership, the party got thumping majority in the Lok Sabha elections, thus becoming the single largest party to get majority on its own after nearly 30 years.