"Without going into the credentials of anyone, I think it will be disastrous for the country to have Narendra Modi as the PM," Singh said.
The Prime Minister also ruled himself out of the race for prime ministership after the next general elections holding that Rahul Gandhi had "outstanding credentials" for the top job.
“After the general elections in a few months time I will hand the baton over to a new Prime Minister. I hope it will be a UPA chosen Prime Minister and our party will work to that end,” he said.
He said the Congress party would decide on its prime ministerial candidate and announce it at an "appropriate" time.
He sought to dispel the negative image of his government and the tag of weak Prime Minister for him.
"I do not believe I am a weak Prime Minister. It is for historians to judge. The BJP and its associates may say whatever they like. If by strong Prime Minister you mean you preside over mass massacre of innocent citizens on the streets of Ahmedabad, if that is the measure of strength, I do not believe that that this country needs that kind of strength,” he said.
On corruption, he said, "As far as charge of corruption are concerned, most of the charges relate to period of UPA I. The coal block allocation as well 2G spectrum allocation, they were both in UPA I. We went to the electorate in 2009 and people gave us mandate to rule again.”
"These charges have been raised from time to time by the media, CAG and courts. They belong to the previous five years. People of India entrusted us with the responsibility to rule Agni. They do not seem to have paid heed to all charges of corruption," he said.
Asked if he could have done something differently on the corruption issue since it has tainted his ‘Mr. Clean’ image, Singh said, “It was I who insisted that spectrum allocation should be transparent and fair. It was I who insisted that the allocation of coal blocks should be on the basis of auction. These facts were forgotten.”
"Opposition has vested interests. Sometimes the media plays into their hands. When history is written we will come out unscathed. This is not to say that there are no irregularities. But the dimensions of the problem have been overstated by the media, by CAG sometimes and other entities," Singh said.
To various questions about his performance and how he would be judged, he said, "I honestly believe that history will be kinder to me than the contemporary media or for that matter Opposition parties."