"In our parliamentary system of governance, the highest office that can, and that must, set the right standards is that of Prime Minister. Unfortunately, this is where India has seen the most disturbing sight of governance deficit," Advani said at a programme at IIT, Delhi.
"It is not that Manmohan Singh himself lacks integrity. But today nobody can deny that the office he occupies lacks integrity," he added.
Advani, however, hit out at the Prime Minister for blaming "compulsions of coalition politics" for anomalies in 2G spectrum allocation.
"He thereby absolved his own office of the blame in keeping its ''Eyes Wide Shut'' while the loot was going on.
The Prime Minister's answer was disingenuous also because it seemed to suggest that corrupt practices were limited only to ministers belonging to coalition partners of the Congress party," Advani said.
The senior leader alleged that not just its allies but even Congress had condoned corruption in the past.
"Indeed, nowhere was the culpability of the Congress party more evident than in the brazen manner in which the investigation into the Bofors scandal has been closed down. The cover-up of this scandal is more scandalous than the original scandal itself," Advani said.
The BJP leader did not spare Singh on the appointment of P J Thomas as CVC either, saying he was culpable as he had been warned by Leader of the Opposition in Lok Sabha Sushma Swaraj about a corruption case pending against Thomas.
"After the Supreme Court quashed the appointment of CVC, the Prime Minister said it was an error or judgement. But couldn't the error have been quickly and easily corrected as soon as Swaraj pointed out that the person being appointed was chargesheeted in a corruption scandal?" he asked.
Incidentally, the issue rocked the BJP last week when differences between Swaraj and others like her Rajya Sabha counterpart Arun Jaitley and party president Nitin Gadkari, on the other, surfaced.
While Swaraj had suggested in a tweet that the matter should rest now after Singh's statement, Advani has attacked the Prime Minister again today.
Advani, who has often targeted Manmohan Singh as a "weak Prime Minister", said the Congress-led government was showing interest in bringing Indian black money stashed abroad only after the Supreme Court had stepped in. BJP has been raising the issue since the 2009 general elections.
He maintained that the main opposition will ensure that 2011 becomes the "Year of Accountability" and will "keep the government on its toes."