Ed Miliband has claimed that he "defined the battleground" for the next general election with his One Nation speech to the Labour party conference.
Prime Minister David Cameron was forced onto the defensive in his own conference speech to the Tories, the Labour leader said.
Mr Miliband used his speech last week to co-opt the One Nation tag coined by 19th-century Conservative prime minister Benjamin Disraeli.
Mr Cameron, bringing the curtain down on the autumn conference season, "talked about and responded to many of the things that I was talking about", Mr Miliband said.
"Now David Cameron has come onto our ground and I welcome that. And if the fight of the next election is who can deliver one nation, I know it's going to be a Labour government led by me standing up for the many, not the few," he said.
Mr Miliband was speaking at Bristol harbourside where he met Labour supporters and the party's candidate for Bristol mayor, Marvin Rees, in November's elections.
"I think what has happened is that Labour has now defined the battleground of the next election: who can build one nation? And the fact that the Prime Minister was forced to respond to that is a sign that we have defined the terms of debate in this country," he said.
"I look forward to the argument now about whether it is right to be cutting taxes for millionaires and raising taxes on everybody else, whether we should be taking action on the forgotten 50% of young people who aren't going to university. Who is going to stand up to the banks and make them work for our small businesses?
"Those are the choices we now face in British politics. Let's have the argument about who can best deliver on those difficult choices."
Speaking later in Cardiff, Mr Miliband said Labour would be spelling out between now and the next general election what One Nation would mean in practice in all major policy areas.