David Cameron has accused Labour of "failing society" as he launched a bid to become Prime Minister. In his keynote address at the Conservative Party Conference in Manchester, the Tory leader asked: "Who made the poorest poorer? Who left youth unemployment higher? Who made inequality greater?" Jabbing his finger as he spoke, Mr Cameron said: "No, not the wicked Tories - you, Labour: you're the ones that did this to our society. So don't you dare lecture us about poverty. You have failed and it falls to us, the modern Conservative Party, to fight for the poorest who you have let down." Following the gloomy package of austerity measures unveiled by shadow chancellor George Osborne on Tuesday, Mr Cameron said beginning to pay off the UK's £175 billion deficit would be among his top priorities if elected. He told delegates: "The longer we wait for a credible plan, the bigger the bill for our children to pay. The longer we wait, the greater the risk to the recovery. The longer we wait, the higher the chance we return to recession." Mr Cameron also vowed to end what he called Labour's culture of "big government bureaucracy" and create "the responsible society". He told delegates: "We are not going to solve our problems with big government, we're going to solve our problems with a stronger society, stronger families, stronger communities, a stronger country. All by rebuilding responsibility." Mr Cameron's speech was preceded by a video message from U2 frontman Bono, who gave a surprise endorsement of the Conservatives.