Prime Minister Manmohan Singh does not need a certificate from the likes of Natwar Singh, AICC spokesperson Abhishek Singhvi said on Wednesday.
"He (Natwar Singh) should not try to give a certificate to the Prime Minister", Singhvi said, commenting on Natwar Singh's remarks against the PM.
He also ridiculed the suspended Congress leader's statement that the Guinness Book of World Records should include Manmohan Singh's name as the Prime Minister who has not won even a municipal election.
"In fact, it is the name of Natwar Singh that should be included in the Guinness Book. For over 40 years, he was with Congress. The party has given him so much and after all this, he is going against it", Singhvi said.
He also criticised the Opposition members, including NDA leaders, who have come in support of the former external affairs minister.
"Let us see for how long they support him and he supports them", he said. "One who extends his hand in friendship is not always a friend", he added.
"All of them have come together for vested interests", Singhvi claimed.