Cameron delivered this crucial speech in October 2005 knowing that he was trailing David Davis in the Conservative leadership race. The speech attacked the Tory status quo, telling representatives that they had to fundamentally change the party, and describing their previous eight years in opposition as a "failure".
As the youngest candidate in the leadership race, Cameron emphasised "fundamental change", saying he wanted people to "feel good about being Conservatives again . . . I want to switch on a whole new generation." This focus on transformation and the apparent ease and charisma of his delivery earned him the tag of the "Tories' Tony Blair".
It can truly be considered the turning point in his leadership bid. He received a three-minute ovation from party representatives after the speech, which was delivered without notes and without a lectern. Ultimately he won twice as many votes as Davis, whose campaign was said to have been marred by a poor conference speech.
So let's build together a new generation of Conservatives. Let's switch a new generation on to Conservative ideas. Let's dream a new generation of Conservative dreams.
We'll be tested -- and challenged. But we'll never give up. We'll never turn back. So let the message go out from this conference: a modern, compassionate conservatism is right for our times, right for our party and right for our country.
Previous speech: Robin Cook, resignation speech, House of Commons, March 2003.