Ed Miliband has urged his party to remember that the post-war Labour government achieved radical social change while also managing to run budget surpluses in a time of austerity.

The Labour leader urged party members concerned about his decision to accept coalition spending plans for 2015-16 to recognise that high day-to-day spending is not the only route to social justice and that Clement Attlee created the welfare state and NHS while also balancing the budget.

In a Guardian interview, Miliband also said he wanted to transfer more power to local government because Britain was far too centralised. He is setting up a local government innovation taskforce because he believes councils are leading the way in developing better ways of delivering services when budgets are tight.

"If you go into the roots and history of the Labour party and think about our most dramatic society-changing government, the 1945 government, we all remember the NHS, building homes, and the family allowance," Miliband said, outlining an argument that he is going to develop in a speech to Labour's national policy forum in Birmingham on Saturday.

"What is less remembered is the other half – yes, they created the NHS, but, believe it or not, they were running a budget surplus. There was wartime rationing. This is a government that banned the import of sardines because they were worried about the balance of payments. It shows a government can be remembered in difficult times for doing great things."

Miliband's decision to announce this month that the party would accept coalition plans for current spending for 2015-16 – but not necessarily for capital spending – has alarmed some in Labour who fear the party is being tied to the coalition's austerity programme.

But Miliband said that showing discipline did not mean the party would not be able to make a difference. And he said he was asking leaders of pioneering Labour councils to produce ideas for the party's policy review because it had to accept that centralisation had run its course.

"Too often in the past central government, Labour central governments, told local government what to do. We are reversing this. We are going to get local government to tell us how it's done," he said.

Miliband's comments about local government echo what Conservative ministers have said about decentralisation, and Miliband acknowledged that the government "claimed to be localist". But he said that in reality it had turned out to be centralising.

Labour has already announced plans to boost council powers, for example, in relation to developers refusing to build on sites with planning permission, and further plans will be set out in a forthcoming "New English Deal" for local authorities.

Miliband also played down suggestions that people were enjoying the benefits of economic recovery. "It certainly feels like a recovery for those at the top," he said, pointing out that bank bonuses are at their highest level since records began in 2000. "But it still feels like a recession for everybody else: wages down, prices up, living standards falling for longer than they ever have in our history."

Meanwhile on Saturday, at a Liberal Democrat conference Nick Clegg will tell his party that it needs to fight the general election in 2015 as a "firm party of government" and on the assumption that it must be ready to form another coalition.

The party will have to campaign in a more united way than it has before, the deputy prime minister will say. "The idea that in a general election we can be under a national spotlight and yet run the campaign as a series of loosely linked byelections simply isn't possible," he will say.