Advani's comments come two days after the Prime Minister asked the BJP leader not to use harsh words against him.
"The Prime Minister has said that we should not use harsh words. What harsh words have I said? The only thing that I have said is that among all the Prime Ministers I have seen since (Jawaharlal) Nehru, Manmohan Singh is the weakest. This is a political comment. Where is the harshness?'' Advani told a press conference.
Making it clear that he will not retract his comments, he said, "The Prime Minister claims he is hurt because I called him the weakest Prime Minister in living memory. If calling a spade a spade is improper, I plead guilty. But it is not me, it is the Supreme Court that has observed that the 2G scam could have been avoided and the estimated Rs 1.76 lakh crore loss to the exchequer saved had Mr Manmohan Singh acted".
Advani, who was equally unsparing about the Congress, said, "With every passing day, the UPA government, nominally led by Manmohan Singh, but commanded by Sonia Gandhi, is exhibiting all symptoms of terminal decline.
"Several of its former ministers are crowding the cells of Tihar Jail on charges of corruption, others are waiting in the queue to enter. Senior ministers of the PM's own party are publicly criticising and contradicting one another," Advani said without elaborating.
"The ruling party's most powerful general secretary makes daily statements that are routinely contradicted by other leaders of the party. Such a condition in a patient would be described as multi-organ failure," he said.
Advani said allies like the Trinamool Congress were distancing themselves from the Manmohan Singh regime which is getting increasingly "unpopular", although they are unwilling to go public at the moment with their frustration.
Advani, who yesterday wondered why Trinamool Congress supremo Mamata Banerjee was being silent about the scams, said, "I miss the outspokenness of Mamata."
He said the disarray and internal dissension within the UPA, which, he thinks, should be renamed as 'Divided Regressive Alliance,' stems from mounting "public anger against the systematic loot of the country".
"This is exemplified by the 2G, CWG, Adarsh, Air India and myriad other scams. India's image in the world is at an all-time low as its governing alliance has become a by-word for corruption," he said.
Asked about corruption charges against his own party leader and former Karnataka Chief Minister B S Yeddurappa, he said, "So far as our party is concerned, we have never been soft on corruption charges. As soon as the Lokayukta report came, we asked him to resign."
Union Agriculture Minister Sharad Pawar's latest remarks against Sonia Gandhi's "extravagant populist proposal" for a Food Security Act were due to the NCP's annoyance at having to bear the cross of the Congress' "nosediving image as a perpetrator and overseer of humongous corruption" in the upper echelons of the government, he said.
On the issue of an estimated Rs 25 lakh crore of black money allegedly stashed away in Swiss Banks, he said, "I hope the government comes out and says what steps it has taken to stop outflow of money to tax havens and bring back black money from those places."
