When the high-profile National Challenge programme was launched two years ago, it was met with screaming headlines about failing secondary schools.
Heads across the country complained loudly about government threats of closure unless more pupils achieved a good set of GCSEs.
By contrast, an initiative aimed at improving primaries - likely to be even more far-reaching - is coming into being almost by stealth.
The World Class Primary Programme is aimed at schools failing to hit exam targets, making insufficient progress and with inconsistent results.
The Government has refused to name the 12 local authorities it has identified with the highest proportion of schools in the programme. But The TES has learned that the list includes Bristol, Southampton, Nottingham, Derby, Sheffield and Rotherham. In Derby, about 85 per cent of its 56 primaries fell into one of the three categories for action.
The programme was launched at the end of last year by Schools Secretary Ed Balls, with a promise of #163;50 million over two years to pay for "superheads", specialist teachers and school improvement partners (Sips). It is also part of wider reforms that will put more pressure on schools to federate into chains.
But heads' union the NAHT fears it will be used to usher in huge structural changes to primary education. Mr Balls himself predicted that 150 primaries with low results could federate under the plans.
Like the National Challenge, participation in the World Class programme will be determined mainly by raw results. The focus will be on the 1,472 schools where less than 55 per cent of pupils achieve level 4 in English and maths.
At the time it was launched, all local authorities were told to submit action plans to the Government for improving primary schools. Most had until the end of March - but the 12 authorities with the highest proportion of schools below the floor target had to comply by the end of January.
The refusal to identify the authorities follows the furore that surrounded the naming and shaming of the National Challenge schools, where fewer than 30 per cent of pupils achieved five good GCSEs including English and maths.
Mr Balls claims never to have used the word "failing" to describe the schools, but the Prime Minister did, prompting vociferous complaints that the policy humiliated and destabilised the very schools it was supposed to help.
That is not to say the World Class initiative does not come with sticks as well as carrots - schools which do not rise above the floor target face a speedy overhaul.
"As you know, you have an existing power to direct a governing body to federate with stronger partner schools where a school is in special measures or a warning notice has been served (and not complied with or successfully appealed)," the Schools Secretary said in a letter to directors of children's services.
"I would like to encourage you to use this power, particularly in the case of schools which have been below the floor for four or more years."
Paul Davies, head of school improvement at Derby City Council, said: "Although we are not happy to be one of those 12 local authorities, we're determined to put that right."
At the core of the authority's plan is greater use of Sips. Currently, there are 15 primaries which have 12 days with a Sip each year, but the authority wants to introduce a sliding scale of support so that, from September, schools will be able to recieve up to 30 days' support a year.
In order to do this, it has agreed to create three new posts on a pay scale of more than #163;60,000 - higher than the average headteacher salary in the city.
Mr Davies said the scheme would also aim to set up partnerships between schools, and it is hoped the Department for Children, Schools and Families will help create links with schools outside the authority as well as within it.
"Ultimately, it comes down to good teaching and that's what is at the heart of our plan," he said. Merging schools, he added, would be a last resort and would not be needed if the plan was successful.
Mick Brookes, general secretary of heads' union the NAHT, has expressed concerns about the initiative and believes it could be used to bring in far-reaching changes to the structure of primary education in England.
"These are the schools doing the toughest jobs," he said. "We do need to look very hard in a very close manner at what is happening to the progress of those children, then put in support mechanisms, such as Sips.
"There are great examples of federations, which have grown from the ground up. Having colleagues support other schools we have no problem with at all. But then saying 'We will close you down' is rhetoric that does nothing for morale."
Mr Balls has said one of the key strategies in the World Class programme should be for authorities to encourage the best schools to set up chains to spread their ideas.
The scheme, which is also open to secondaries, means that primaries apply to become an accredited provider, which links them with two underperforming schools. The first 16 primary school providers were announced last month.
Robert Hill, a former Downing Street education adviser, is a supporter of chains, but has said the Government needs to be clearer about what it expects in the next 10 years.
In a paper for the National College for Leadership of Schools and Children's Services, he advised against clustering primaries together for the sake of it.
Instead, he suggests that all primaries judged inadequate by Oftsed are automatically incorporated into a chain.
"The programme does provide a much clearer steer towards greater collaboration," he said.
"The Government could, however, go further and adopt an approach similar to the Dutch one ... expecting all primary schools to be part of an accredited primary school group within a defined period of, for example, five years."
The relatively hush-hush way in which the policy has been introduced so far, however, means that a number of schools due to be involved from September are still unclear about what it will mean.
"We know as little as anybody else," said one head, who wanted to remain anonymous. "We are still doing our best for children, still doing our best for school.
"This doesn't do anything for morale. It is like being a school which is named and shamed at the bottom of the league tables - it feels exactly the same as that."
One head due to be involved in the World Class Primary Programme told The TES he is worried that officials will expect quick-fix solutions.
Federations could be the answer for some schools, but solutions should not be imposed from above, he said.
He added: "Teachers are the best teachers of teachers. I have never known two schools to collaborate and for that not to have a good effect. But the programme is a little bit vague.
"Leadership is now such a variegated job. We can't possibly carry on with the model of one head in each school ticking every box.
"There is a mood in this authority that we want to improve. But there is concern that these things are a long haul. There are some quick wins in primaries, but other problems are complicated and do take longer."
CHAINS AND GOOD PRACTICE TO THE TUNE OF #163;50M
Announced in December 2009, the programme will spend #163;50 million over two years on improving schools, national leaders in education, school improvement partners (Sips) and specialist teachers.
The 12 authorities with the highest proportion of schools below the 55 per cent floor target had to return improvement plans to the department by the end of January. Other authorities' plans were due by end of March.
The first 16 primaries to be accredited school providers were announced in March.
The programme will spread best practice through school-to-school visits - 60 host schools will offer free half-day visits from September, with online feedback.