New Delhi: Breaking his silence over BJP's prime ministerial candidate Narendra Modi, Prime Minister Manmohan Singh on Friday launched a scathing attack on him saying it will be a disaster for the country if such a person became the Prime Minister of India. br br "Without going into the credentials of anyone, I think it will be disastrous for the country to have Narendra Modi as the PM," said Singh at his second press conference with media in his second tenure.