If the Government’s pledge to provide pre-school places for all three and four-year-olds sounded good back in the heady days of Labour’s 1997 election victory, even the party’s biggest supporters must have wondered how it was going to be done.

And yet, six years on, the figures look good: every four-year-old is entitled to a place in a reception class or nursery and, by next April, five two-and-a-half-hour nursery sessions a week will be available free of charge to every three-year-old for three terms.

“It is quite an achievement,” says Margaret Lochrie, chief executive of the Pre-School Learning Alliance. “People here have campaigned for decades for what people in some other countries have had as a right for generations.”

So, a political master stroke: the Cinderella of the education world is coming to the ball after all. Or is she? A closer look at how provision for three-year-olds is panning out reveals a patchier picture. Like other government policies, this one depends on a mix of private and public sector which has had some unforeseen results.

For a start, it is not quite clear who is receiving the latest nursery education grant - pound;275 million this year alone, rising to pound;319m next year.

“It is difficult to keep a handle on who is providing this education,” says Nansi Ellis, primary education adviser at the Association of Teachers and Lecturers. “Some of these places are in church halls. Quite often you cannot even get a letter to them.”

The Office for National Statistics says that figures on daycare, due last March, are not reliable enough for publication. And even the Department for Education and Skills does not know how many schools have set up nursery classes, and figures for next year are difficult to project “because it is a fluid area”.

This blip in record-keeping could be down to the fact that the expansion of nursery places for three-year-olds has largely depended on the private and voluntary sector.

It has been the job of the 150 early-years development and childcare partnerships to chivvy along nurseries and playgroups to join the national education framework, and ultimately ensure the Government remains on target.

As a result, some 70 per cent of three-year-olds now have their free nursery place - some 55 per cent of those places are with private, voluntary and independent providers. If the private sector was the major loser when four-year-olds decamped en masse to school reception classes, you could be forgiven for believing they have hit the jackpot this time.

But the reality is more complicated. While the Government has been encouraging private providers to step in, it has also been busy with its own projects: Sure Start, early excellence centres and neighbourhood nurseries. So in some parts of the country, where public money is being pumped into nurseries, private and voluntary providers are feeling the pinch.

Having jumped through all the Government’s hoops - not least putting the foundation stage curriculum in place - they face the prospect of being put out of business.

Keith Beardmore, the owner of an 80-place nursery in Blackpool who represents the town’s 28 private nurseries on its early-years partnership, blames the “South of England syndrome”.

“It is no good saying the South-east is in desperate need of childcare places and treating everywhere the same. We do not need more childcare places up here. The money should have been directed at training. The Government has got to look at this more regionally.”

He has a point. Blackpool, in common with many northern authorities, has a long tradition of maintained nurseries: it has 10 with two more in the pipeline. But designated as an area of deprivation, it is also in the frontline for funding from other areas of the Government’s childcare strategy, designed to boost the local economy by making it easier for parents to work.

It has one sure start centre already open,with another due soon. An early excellence centre and another sure start are in the pipeline. And yet Mr Beardmore’s nursery is running 20 per cent under-occupied.

Some of his colleagues say nearly a third of their places are empty.

Naturally, a question mark now hangs over their future.

If these places were not needed in the long term, why has so much time and money been ploughed into them to bring them within the national education framework?

“The Government has targeted the most deprived areas first, but it is creating havoc,” says Rosemary Murphy, chief executive of the National Day Nurseries Association. “In some areas there is a surfeit of provision. I’d like to see a period of consolidation.

“Some of these loyal providers have risen to all the challenges of inspection and the rigours of delivering the foundation stage. We would be doing them a disservice if we let them go under.”

If there are too many places in some parts of the country, in others there are far too few. Switch to London and the South-east - where there are fewer maintained nurseries and places are often restricted to the “oldest” three-year-olds - and parents are still pounding the streets desperate to find a place for their child.

When they do, many have been told that promised funding has been delayed or restricted.

For the regional differences are not confined to the availability of places. The Government’s grant, which works out at pound;406 for an 11-week term per child - or pound;2.95 an hour - amply covers the cost of five two-and-a-half-hour sessions a week in the north. But in the South, where a nursery session can cost pound;4 an hour or more, the grant amounts to nothing more than a subsidy.

Cross-examined by the Commons education select committee as recently as December, Catherine Ashton, the Sure Start, early-years and childcare minister, claimed she had not heard of any nurseries charging top-up fees.

And yet there are plenty of examples in the South-east. In Kent, 66 per cent of three-year-olds now have free places. The lion’s share is in the private and voluntary sectors.

“In common with other areas of the country, we will have providers offering places that are free with no top-up costs,” says Alex Gamby, head of early-years and childcare in Kent.

“But if you offer a session longer than two-and-a-half hours, or something additional to the foundation stage, this allows providers to levy an additional charge.”

Quality is also something of a lottery. In Blackpool, which is in the process of creating a huge pre-school market-place, it will be quality provision which survives. But in areas where places for three-year-olds are still being sought, quality could end up being a secondary consideration.

Standards still vary widely. Indeed, the Office for Standards in Education, which since 2001 has registered and inspected all childcare facilities, is about to start grading them.

The foundation stage curriculum, which focuses on learning through play, is undoubtedly the unifying force of the pre-school sector, but its effectiveness depends on the staff who deliver it. For the moment, qualifications can range from graduate-level teacher to nursery nurse through to untrained volunteer.

“A lot of positive things are going on around the nursery school sector,” says Jenny Rabin, project manager for Early Education, formerly the British Association of Early Childhood Education. “But it needs to be under-pinned by quality. People have to accept that they need to keep training.”

Despite what has been achieved so far, there is still a long way to go before every three-year-old enjoys a free daily session in a high-quality setting.