As many as 1,000 Sure Start children's centres around the country may have closed since 2009, analysis by an educational charity has suggested.
The national database recorded a 14% drop in centre numbers from 3,632 in August 2009 to 3,123 in October 2017, but this "may understate the true figure", research by the Sutton Trust found.
The report, undertaken by a group of Oxford University academics and entitled "Stop Start: Survival, decline or closure? Children's centres in England, 2018" argued the drop was "more than 30%" - twice as many as reported.
The analysis, it argued, showed "decline, both in numbers and services, but also adaptation and a struggle to survive".
It said: "Many closures announced locally were not yet reflected in the database: our survey showed a 16% drop.
"If we only count 'registered centres', the drop since 2009 was more than 30%, suggesting that more than 1,000 centres nationally might have closed.
"There is now growing evidence of a further wave of large-scale closures in the pipeline as a 'tipping point' is reached."
Researchers surveyed local authorities for the reasons behind the changes in provision, with 84% citing financial pressures and 69% reporting a budget decrease in the last two years.
Eighty per cent of local authorities reported a move away from access for all towards targeting of individual high-need families.
It noted: "Services are now 'hollowed out' - much more thinly spread, often no longer 'in pram-pushing distance'. The focus of centres has changed to referred families with high need, and provision has diversified as national direction has weakened, with local authorities employing a variety of strategies to survive in an environment of declining resources and loss of strategic direction."
The report noted that in August 2009, 54% of all centres were located in the 30% most disadvantaged areas, but by late 2017, the overall national picture was "radically different".
It said: "Indeed, it is difficult to see it any longer as a truly 'national programme' as there is so much local variation in what is now provided - not so much a 'postcode lottery' as dependent on which local authority serves your area."
The report concluded a high proportion of the closures took place in a few areas and by 2017, 16 authorities closing 50% or more of their centres "accounted for 55% of the total number of closures nationally".
It added that measured on the basis of income deprivation affecting families with children, there had been "only marginal change" since 2009 in the location of centres in the poorest 30% of neighbourhoods (with 54% in 2009 and 52% in 2017) - although there were "critically fewer centres in all areas".
The charity's report called on the Government to maintain a national register of children's centres establishing minimum levels of provision.
Sutton Trust founder Sir Peter Lampl said: "It is a serious issue that the services that Sure Start centres offer are much more thinly spread than they were a decade ago.
"Additionally, since 2010 there has been a precipitous decline of 30% in the number of Sure Start centres. Thousands of families are missing out on the vital support they provide.
"The Government should complete its long-promised review of the programme. Instead of trying to serve all age groups, children's centres should reconnect with their original purpose of promoting child and family development for the 0-5 age group."
A Government spokesperson said: "Councils will receive more than £200 billion for local services, including children and young people services, up to 2019-20.
"In addition to this we are investing more in childcare support than any other government - around £6 billion a year by 2019/20.
"It is right that we give councils the freedom to decide what services they provide for their communities as they are best placed to understand local needs and how best to meet them, whether through a children's centre building, a family hub, or another model."
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