Labour leadership hopeful Ed Balls said yesterday he is the man to take Labour back to No 10.

As the campaign to find Gordon Brown's successor gains momentum, the former schools secretary said he is the only candidate to hold on to the "New Labour understanding".

He said the party must cling to New Labour's foundations while moving on from the "politics of internal definition" employed during Labour's second term.

"The founding New Labour insight of 1997 is as relevant to 2010 as 1997 – that we cannot be a romantic party of the opposition, we have to be a credible party of government," he said.

"Of all of the candidates, I'm the only one who says we must hold onto that New Labour understanding because, to me, New Labour was 1994 to 1997, us translating from being a party of opposition to a party of government, understanding that our radicalism had to be based on credible foundations, that no one would trust you on public services unless you were trusted on rates and inflation.

"In my mind, we lost our way in the second term. The leadership gave the impression they would get their definition by internal debate and division – you are either a reformer or not a reformer, either New Labour or Old Labour, and we ended up with policies that became very divisive.

"This was a politics of internal definition which ended up, I'm afraid, saying to many party members and trade union members working in the public sector: you are the kind of people we are against.

"I will never put petty party advantage before doing the right thing by the country.

"But I'm also Labour, the reason I'm in politics is because the values which shaped my view of the world are the opposite of what I think Clegg-Cameron want to do."