In a blog published Sunday, Advani called the prime minister and the Congress president "Dr. Manmohan - Sonia duo", and called the cash-for-vote scandal the "most disgraceful scam".
"... I hold that the most disgraceful scam that came to light during UPA-I was the Cash-for-Votes Scam," he wrote.
The Bharatiya Janata Party leader also drew parallel between cash-for-vote and the scenes witnessed during introduction of the Telangana bill.
"No less shameful for the prestige and reputation of the Indian Parliament than this Cash-for-Episode Scam that occurred in UPA I's time is the ugly scenes witnessed under UPA II," he said.
Advani added: "Limits of unsavory behavior were crossed... when apart from a repeat performance of the previous day a Congress Party MP pulled out a black pepper spray and started spraying it all around so that several MPs including Sushma Swaraj had tears in her eyes, and many others were seen coughing in acute discomfort."
The BJP leader also said Manmohan Singh began his tenure with a "clean personal reputation", but at the end of his tenure "he would leave behind him a record of having presided over the most corrupt government in Independent India".
Advani said that most of the scams have come to light only because exposures made by the Comptroller and Auditor General or the judiciary.