"I have never seen such a weak prime minister... he has been the weakest prime minister ever," he told an election meeting here echoing PM's former media adviser Sanjay Baru's book 'The Accidental Prime Minister'.
Advani alleged that Singh hid his failure to rein in corruption and scams behind compulsions of coalition politics, but he was too weak a Prime Minister to prevent corruption among ministers in his government.
"The Prime Minister should not have allowed corruption and scams to take place in the first place and exercised his authority to crack the whip against errant ministers," he said.
But it was not to be as he allowed himself to be manipulated by Congress leadership given his weakness as a person, which had denigrated the institution of prime minister and brought in chaos all around, Advani alleged.
Criticising the Congress-led UPA government for price rise, corruption and scams, Advani held that it would be go out of power at the Centre and in several states like Uttar Pradesh and Bihar as in 1977 when the Janata Party had formed a government after the then Prime Minister Indira Gandhi imposed Emergency in 1975.