Media playback is unsupported on your device Media caption David Cameron: "I think we're onto a really big idea, a really exciting future for our country"

David Cameron has launched his "big society" drive to empower communities, describing it as his "great passion".

In a speech in Liverpool, the prime minister said groups should be able to run post offices, libraries, transport services and shape housing projects.

Also announcing plans to use dormant bank accounts to fund projects, Mr Cameron said the concept would be a "big advance for people power".

Voluntary groups and Labour have queried how the schemes will be funded.

The idea was a central theme in the Conservative general election campaign and Mr Cameron denied that he was being forced to re-launch it because of a lack of interest first time around.

While reducing the budget deficit was his "duty", he said giving individuals and communities more control over their destinies was what excited him and was something that had underpinned his philosophy since he became Conservative leader in 2005.

"There are the things you do because it's your passion," he said.

"Things that fire you up in the morning, that drive you, that you truly believe will make a real difference to the country you love, and my great passion is building the big society."

'People power'

The prime minister said community projects would be established in four parts of the UK - Liverpool; Eden Valley, Cumbria; Windsor and Maidenhead; and the London borough of Sutton - as part of efforts to "turn government completely on its head".

Each of the project areas - which Mr Cameron said had approached ministers asking to be involved - will be given an expert organiser and dedicated civil servants to ensure "people power" initiatives get off the ground.

Analysis The 'big society' is David Cameron's Big Idea. His aides say it is about empowering communities, redistributing power and fostering a culture of volunteerism. Perhaps no wonder then that Tory candidates during the general election found it difficult to sell the idea to voters. So why is David Cameron returning to this theme ? In part because he does view it as his answer to Big Government - but there are also more basic political motives. First, it's about providing a different agenda to the day by day litany of cuts, cuts and more cuts. Second, it is - as Eric Pickles has acknowledged - about saving money. If people are doing things for free then you don't have to pay public servants to do them for you. So beneath the grand-sounding philosophy there is hard-nosed, practical politics behind the 'big society' message. More analysis from across the web

The initiatives being championed include a local buy-out of a rural pub, efforts to recruit volunteers to keep museums open, support to speed up broadband supply, and giving residents more power over council spending.

These schemes and others in the future, he said, would represent "the biggest, most dramatic redistribution of power from elites in Whitehall to the man and woman on the street".

In the past, he said, the talents and initiative of people had been wasted, claiming that over-centralised government had turned public sector workers into the "weary, disillusioned puppets of government targets".

Mr Cameron acknowledged the transformation he was seeking would not happen overnight and stressed it was not a matter of the government stepping aside and letting people fend for themselves.

"Of course there is not one lever you can simply pull to create a big society," he said.

"We should not be naive enough to think that simply if government rolls back and does less, then miraculously society will spring up and do more.

"The truth is we need a government that helps to build a big society."

As well as encouraging greater volunteering and philanthropy, Mr Cameron confirmed plans to use funds stuck in dormant bank and building society accounts to enable "some of the most dynamic" charities, social enterprises and voluntary groups to take over the running of public services.

It is hoped that hundreds of millions of pounds will eventually be available in start-up funding through a Big Society Bank, to be matched by private investment.

'Cut-price alternative'

Mr Cameron rejected suggestions that the plans were "cover" for substantial cuts in public services due next year and that the public were either confused by or uninterested in the proposals.

"I don't accept that people don't understand what this is," he said.

Everyone was aware of the "great work" that volunteers were already doing in communities up and down the country, he said, and it was his ambition to simply expand this.

PROPOSED INITIATIVES Cumbria: relocating community centre, building renewable energy project, community buyout of pub, spreading broadband access

relocating community centre, building renewable energy project, community buyout of pub, spreading broadband access Windsor and Maidenhead : public say over local spending decisions including parks budgets, further powers to parish councils

: public say over local spending decisions including parks budgets, further powers to parish councils Liverpool : increased volunteering at museums, developing neighbourhood media and digital content

: increased volunteering at museums, developing neighbourhood media and digital content Sutton: working on sustainable transport services, developing youth projects, creating "green living" champions

"It is incredibly simple idea and one, I think, is catching on," he said.

Shadow Cabinet Office minister Tessa Jowell called Mr Cameron's speech "a brass-necked rebranding of programmes already put in place by a Labour government".

She added: "We welcome the coalition's decision to continue our work in partnership with local communities, but these projects are dependant on funding and resources being put in place.

"It is therefore highly unlikely that civil society will become 'bigger' due to the large public spending cuts that are being put forward by this government."

Voluntary groups broadly welcomed the idea but expressed concerns about how equipped they were to take on more responsibility, given that public funds were likely to be cut as part of the budget squeeze.

"It is going to be very challenging for them to play a bigger role if they have less resources to do it," said Ben Kernighan, from the National Council for Voluntary Organisations.

And union leaders said public services must be based on certainty of provision and not whether there were enough volunteers on any given day.

"Make no mistake, this plan is all about saving money," Dave Prentis, general secretary of Unison, said.

"The government is simply washing its hands of providing decent public services and using volunteers as a cut-price alternative."