Prime Minister David Cameron has promised to "get Britain on the rise" by unleashing the power of enterprise and aspiration to overcome the economic crisis.

In a sometimes sombre address to the Conservative conference in Birmingham, Mr Cameron warned that the UK faces an "hour of reckoning" in which the decisions it makes will determine whether it will "sink or swim, do or decline".

The effects of the downturn, coupled with the rise of new economic powers around the globe, mean that Britons can no longer assume that their country will be able to continue to earn its living as a major industrial country, he said. But he told delegates that he was confident that Britain will "rise to the challenge" and harness the "individual aspiration and effort" of its people to ensure prosperity in the future.

He promised to support "the doers, the risk takers, the young people who dream of their first pay cheque, their first car, their first home and are ready and willing to work hard to get those things".

In personal passages, Mr Cameron revealed how the example of his disabled father taught him the keys to success and to Britain's recovery - "Hard work. Strong families. Taking responsibility. Serving others."

Mr Cameron acknowledged that the Government's deficit reduction plan was "taking longer than we hoped", which he blamed largely on the eurozone crisis. But he insisted that Britain was "on the right track", saying: "Yes it's worse than we thought, yes it's taking longer, but we are making progress."

He insisted that the country will overcome its challenges, because "at our best, we're unbeatable". And he promised to reform welfare, planning and education to unlock enterprise and growth and support aspiration.

He said: "Let us here in this hall, here in this Government, together in this country make this pledge - let's build an aspiration nation. Let's get Britain on the rise. Deficit, paid down. Tough decisions, taken. Growth, fired up. Aspiration, backed all the way. We know what it takes to win - to win in the tough world of today, to win for all our people, to win for Britain. So let's get out there and do it."

Mr Cameron was scathing about Labour's Plan B to stimulate growth by borrowing more for investment, which he described as "a massive gamble with our economy and our future". Dismissing Ed Miliband's bid to snatch the Tory One Nation slogan for his party, he denounced Labour as "the party of one notion - more borrowing".

He won applause from delegates by praising the role of the armed forces in Afghanistan, the Queen's involvement in the Jubilee celebrations and her parachuting cameo in the Olympics. And he even had warm words for Boris Johnson, who has been touted this week as a rival for his job, hailing him as "the man who put a smile on our face, the zinger on the zip-wire".