Alan Milburn has broken his summer of silence with a call for the prime minister to stop talking like a "competent administrator".

Writing in the Guardian, the former health secretary said there is a "sense that the government is drifting" and a "fog of doubt" hanging over Tony Blair.

Urging the government to adopt more "conviction politics", Milburn argued that Labour needs to get a sense of direction.

"Labour is in power to change things, not keep them the same, transformation not consolidation," he writes.

"Above all the public want to know where we are taking the country."

The warning came as Peter Mandelson conceded that the government is in "politically choppy water".

Addressing the North West Business Convention the former trade secretary said the prime minister would weather the storm.

"At present the government is steering its way through what you might call politically choppy water," he said on Friday.

"But I think by now I know Tony Blair and his Cabinet reasonably well.

"Adversity will make them even more determined not to duck the real challenges facing this country."

Milburn, who resigned to spend more time with his family, also warned Blair that being bold is not enough.

"Boldness is a means not an end. There must be a purpose to it. Faced with a tide of uncertainty, now, more than ever, Tony Blair has to spell out what the purpose of New Labour is," he said.

"He has to communicate it in terms of our values and vision for Britain. For me - and I suspect for him - it is simple enough. It is about creating a fair future for all."

Calling for "democratic socialism" he argued that Labour must "empower people who have traditionally been without".

"New Labour should not be neutral on where power, wealth and opportunity lies. That is why Labour's constitution - carried on every membership card - argues they should be 'in the hands of the many, not the few'," added Milburn.

But he warned that this does not mean a return to an old Labour values.

"The reason I am optimistic, despite the problems the government faces, is that, fundamentally, the left's values are more relevant in today's world than the right's. This is not to argue for retreat into an old Labour ghetto," he wrote.

"In health or education the worst thing to do would be to move backwards towards a monolithic old style take-it-or-leave-it service.

"We should move forwards to a service where there is diversity in supply and where choice is extended to those with without wealth.

"The well-to-do have always had the best service. It is time for some redistribution here too."

Milburn also dismissed those who believe the prime minister has lost his appeal to voters.

"We need to be both more Labour and more New Labour. We need to renew both," he said.

"Nothing terrifies our opponents more than the fusing of Labour's values of fairness with this modern approach.

"Every thinking Tory knows that the biggest enemy the Conservative Party faces is Tony Blair."