His defection was announced by the Senate President, Ahmad Lawan, after the lawmakers resumed plenary.
Shekarau had defected from the All Progressive Party to the New Nigeria Peoples Party sometime in May but his defection letter was read on Wednesday.
The Senator has also since received the NNPP membership card at his Giginyu ward in the presence of the party’s top echelons and politicians like the presidential candidate of the party, Dr Rabiu Kwankwaso, and a former member, House of Representatives, Sulieman Sumaila.
Like others, Shekarau in his resignation letter, cited injustice, marginalisation and unfairness by Kano State Governor, Abdullahi Ganduje as reasons for his exit from the party.
His letter read, “I kindly write to formally notify you of my resignation from the All Progressives Congress, and declaration for the New Nigerian People’s Party.
“My resignation from the APC was born out of the marginalization of all major critical stakeholders, and lack of internal democracy, in the Kano State chapter of the APC, plus the total absence of the principle of inclusiveness in the affairs of the Party and its Government at all levels in the State.
“All efforts to resolve the long protracted crisis in the State, in the last two years, including the involvement of the National Headquarters of the APC, failed due to the non-cooperation of the Kano State Governor and party leadership in the State.
“Consequently, after due consultation with like-minds and millions of our supporters in the State, we decided to withdraw our membership of the APC and moved to the New Nigeria People’s Party.
“Accept, please, my fraternal goodwill and continued cooperation at all times.”
After the announcement, Senate President directed the Chief Whip to lead Shekarau to the opposition row in the red chamber.
Shekarau was a former Nigerian minister of education and two-term Governor of Kano State in Nigeria.
He was elected in April 2003 and reelected in April 2007. He was one of the candidates who aspired to become president in the Nigerian general elections of 2011.