I'm ready for power - Cameron

British opposition leader David Cameron declared himself ready to take power yesterday, in a rousing address to his Conservatives' last annual conference before elections he is tipped to win.

But in a keynote speech preceded by a video message from U2 frontman Bono, the media-savvy young leader warned of tough choices as Britain emerges from recession.

"Don't get me wrong, I have no illusions. If we win this election, it is going to be tough," he said, adding: "None of this will be easy. We will be tested. I will be tested. I'm ready for that."

"There is a steep climb ahead. But I tell you this - the view from the summit will be worth it," he added, closing the four-day Tory conference.

The 42-year-old moderniser has transformed the opposition Conservatives in four years as leader. He took over after three election defeats and the party is now well ahead of Prime Minister Gordon Brown's Labour party in the polls.

The latest YouGov poll for Sky News, a daily survey carried out during the conference and published on Wednesday, put the Conservatives on 43 per cent and Brown's Labour party on 29 per cent.

Following an introductory video from Bono, who praised the party's commitment to foreign aid, Mr Cameron launched into a highly personal vision of what he stood for and what a Conservative Britain would look like.

He said that after the death of his six-year-old disabled son, Ivan, in February "you think about what you really believe and what sustains you", and reaffirmed his emphasis on the family and community as key social structures.

Britain had lost its way under 12 years of Labour government, he said, blaming an overpowering state and accusing Brown of economic mismanagement that, coupled with the recession, left it facing huge challenges.

"Our national debt has doubled in the last five years and our annual deficit next year will be over £170 billion... that's a massive risk to our economy," Mr Cameron said, warning efforts to cut the debt must start soon.

Building on the austerity measures announced this week, Mr Cameron warned there would be "painful" cuts to public spending ahead as his party took the "responsible" path to getting the nation's finances back in the black.

In a bid to practice what it preaches, the party has reportedly imposed a ban on drinking champagne at the conference, although Mr Cameron was among those snapped with a glass earlier this week.

The Tory leader also reiterated a promise to hold a referendum on the European Union's Lisbon Treaty if it has not yet been ratified - a pledge that has sparked concern in Brussels but went down well with delegates here.

Mr Cameron again refused to say what his party would do if the treaty is already ratified by EU member states by the next election, but repeated his desire for Britain to take back powers over social and employment issues.

Foreign affairs spokesman William Hague earlier also won applause for his speech when he repeated his opposition to the new post of a European president that would come into force under the treaty.

"We seek a European Union that acts by agreement amoung nations, rather than by placing its own president or foreign minister above any nation," he said.

Mr Cameron also addressed Afghanistan, promising to "send more soldiers to train more Afghans" to stop the country becoming a haven for terrorism.

He also confirmed that the former head of the British army, Richard Dannatt, will act as the Conservatives policy advisor, join in the House of Lords and could even be made a minister if they win the next election.

Mr Dannatt has repeatedly criticised Mr Brown's government for not giving enough resources to the war in Afghanistan.