Murang'a Senator Irungu Kangata now says the promoters of the BBI should drop the push and instead use parliament to enact legislation to implement some of the progressive proposals in the bill.
The former Senate Majority Whip said the BBI is legally and technically dead after the High Court ruling that declared the process unconstitutional, null and void.
He said some of the progressive proposals in the bill, such as the creation of the Ward Development Fund and increasing allocation to counties can be achieved without necessarily sending the country to a referendum.
The lawmaker said the BBI process had several legal flaws that he had raised in his letter to the President late last year.
"I have been vindicated. I had said that BBI had several problems. The courts have said the same thing that I raised in my letter," he said.
Last December, Kangata penned a controversial letter to President Uhuru Kenyatta, discrediting the drive's popularity in Mt Kenya and decrying use of provincial administration officers in the process.
Addressing a press conference at his office in Upper Hill, Nairobi on Saturday, Kang'ata said that chances of the Court of Appeal overturning all the 20 grounds raised by lower court are minimal unless the 'system' coarces the Court.
"I urge the promoters of BBI to drop the appeal because chances of it succeeding are very minimal," he said.
He added that even in the worst scenario that the Court of Appeal vacated all the lower court's ruling, the BBI morale has been punctured by the High Court.
He urged the promoters to drop the contentious and undesirable clauses from the bill such as expanding parliament and the executive at the expense of the taxpayer.
The progressive proposals, he said, can be implemented through parliamentary processes without necessarily holding a referendum.