Cameron speech: We are here to fight
David Cameron has said the Conservatives have "never been more up for the task of turning our country around", at the party's spring conference in London.
The prime minister sought to reassure grassroots members about the party's direction after its defeat at last month's Eastleigh by-election.
The poll loss has prompted some Tories to demand a shift to the right.
Mr Cameron told party activists: "We are here to fight. We are here to win."
He said that with fewer than 1,000 days until the next general election, activists needed to get the party's message out and "win the majority our country desperately needs".
"Anyone in this party who is in any doubt who we should be fighting, what we should be debating, where our energies should be focused, I tell you - our battle is with Labour," he said.
Labour said the government needed to build a country where "prosperity is fairly shared" - but this would not happen under Mr Cameron.
'Battle for Britain'
Opening his speech, the prime minister said he had a "very clear message" for his party.
"We are people who love our country, who believe in Britain's greatness - and believe in restoring it," he said.
He said it was an "honour" and a "privilege" to serve the country in "its hour of need".
"This is a battle for Britain's future we are engaged in," he said.
"So let the message go out from this hall and this party: We are here to fight. We are here to win.
"And we have never been more up for the task of turning our country around."
Mr Cameron also outlined what he saw as the coalition's main achievements and told activists the party was giving people the "tools to succeed".
He said he was following the same Tory values of past prime ministers, such as Margaret Thatcher and Winston Churchill.
"We want people to climb up through their own efforts, yes, but in order to climb up they need the ladder to be there in the first place, the family that nurtures them, the school that inspires them, the opportunities there for them," he said.
"Great Conservatives down the generations have put those ladders in place: when Churchill invented the labour exchanges that helped people into work, when Macmillan built new homes, when Thatcher fired up enterprise so people could start their own businesses.
"That is what we're doing in the Conservative Party right now."
He said he also wanted to focus on what the party was doing for young people.
"We are building an aspiration nation, a country where it's not who you know or where you're from but who you are and where you're determined to go," he said.
Mr Cameron reflected on adoption rules, saying barriers to mixed-race adoption were "wrong" and would be changed.
On education, he said he wanted the system to be "like the pushiest, most sharp-elbowed, ambitious parent there is" and he wanted it to "be the norm" for every school leaver to start an apprenticeship or go to university.
He also pledged more help for people who want to own their own home.
On Labour's opposition to benefit cuts being rolled out as part of the deficit reduction programme, Mr Cameron said they were "patronising people, patting them on the head and putting a benefit cheque in their hands".
Michael Dugher, vice-chairman of the Labour Party, said Mr Cameron's leadership was "defined by failure and broken promises".
"When the Tories talk about aspiration, they mean looking after their friends at the top, whilst people on low and middle incomes can go whistle," he said.
"Cameron gives speeches claiming he's helping people, but he's actually delivering a tax cut for millionaires whilst asking millions of working people to pay more.
"We need a change of direction with a One Nation Labour government to build a country where everyone has a stake and prosperity is fairly shared. Fat chance of that with David Cameron."