Congress president Sonia Gandhi on Wednesday slammed opposition parties for targeting the integrity of Prime Minister Manmohan Singh, who, she said, was widely known for his honesty and against whom there has not been an iota of corruption allegations. ?It is shameful to target prime minister?s integrity,? Gandhi said. ?Everyone knows he (Singh) is 100% above reproach. I will remind Opposition of 2009 when they made it a point to destroy the image of Prime Minister Singh. How they attacked him during the campaign.? ?What was the result? That should be a lesson for Opposition,? Gandhi told reporters referring to electoral success of Singh and UPA in the 2009 assembly election.