How far will Cameron go on opening up public services?
Justify your monopoly or compete with outsiders.
That is David Cameron's new message for public servants
He wants to up-end a debate that has typically seen politicians explaining why they want a bigger role for the private sector or charities in delivering services.
Instead, he says, the state should justify why it should ever operate a monopoly.
It will "signal the decisive end of the old-fashioned, top-down, take-what-you're given model of public services", says Mr Cameron.
For the general secretary of the TUC Brendan Barber it is a proposal to "privatise everything that moves" and "a naked right wing agenda".
Already journalists are asking how far the prime minister wants to go. Mr Cameron has only excluded the areas of national security and the judiciary from this sort of thinking.
So his spokeswoman was pressed repeatedly on whether the police would have to explain why they should enjoy a monopoly on law enforcement.
In the end she said police forces were not about to be privatised.
The details of this plan will be set out in a white paper on public service reform due next month. But the thrust of the recommendations is already becoming clear.
Close to the government's heart is the idea of letting public workers themselves take control of the services they provide.
It has already set out plans to help them form mutual organisations and to give them the legal right to do so. It hopes the new Big Society bank will provide capital.
Worker-led groups like these would prove less controversial than privatisation but they would not exclude the private sector. The mutuals would be able to form joint ventures with companies.
The White Paper is likely to set out technical changes that will make it easier for small firms and charities to compete for existing government contracts.
A recent consultation on commissioning structures secured few big headlines but the government believes this will be key to achieving its aims.
Government plans are expected to contain more details on personal budgets that allow citizens to have a say in how public money is spent on the services they use.
Trials of personal budgets for disabled adults are under way. Similar plans have been announced for those with special educational needs and children with disabilities and long term health conditions.
The idea is popular with policymakers who believe it gives people more control and allows them to buy services outside the public sector, introducing fresh competition.
Those who aspire to provide services will look closely for detail of payment-by-results, which is also expected to feature in the White Paper.
If the structure is too generous, savings will not be made. If it is too tight-fisted small providers will struggle to compete with bigger and better resourced rivals.
Much of this comes as no surprise. Education Secretary Michael Gove's plans to allow people to set up schools, and plans from Health Secretary Andrew Lansley to allow health providers to compete in a regulated market both indicate the government thinking.
Rehabilitation and work programme services will be provided on a payment-by-results basis.
Private firms have had a role in public services for many years. The idea of personal budgets has been much discussed since the Eighties and was extensively piloted by the Labour government.
The controversy is nothing new either. One person's injection of openness and innovation is another's assault on the public sector.
Ministers are aware of their opponents. So expect to hear much about "fair access" when the White Paper is published.
The government believes the changes will not stop taxpayers getting the services on which they rely and it will try to convince the public of that.
These ideas are central to David Cameron's Big Society.
But they will spark a debate on a question which predates that idea by decades - whether allowing public services to be delivered by other bodies represents a salvation or a threat.