More nursery education should be carried out in schools to prepare children better for later education and help bridge the gap between rich and poor, the chief inspector of schools has said.
Sir Michael Wilshaw warned that too many early years education providers are failing to teach youngsters "social, emotional and learning skills" and get them ready to start primary school.
Pupils from poorer backgrounds are also too often falling behind their more privileged peers by the time they reach school age, but bringing "structured" early years provision into a school setting would help put them on equal footing.
His comments came ahead of Ofsted's first Early Years Annual Report, published today, which will call for a radical shake-up of early years education in England.
The report will highlight the continuing gap between children from disadvantaged backgrounds and more affluent youngsters, saying too many children are not ready for school.
Only a third of children from low income backgrounds reach what is considered a good level of development at the early years stage, and once behind will struggle to catch up with their peers, Ofsted said.
Sir Michael will say: "Too many of our poorest children are getting an unsure start because the early years system is letting them down."
But he will argue that this doesn't have to be the case, saying: "There are areas of the country, particularly London, where most children do well and the gap between advantaged and disadvantaged is closing.
"There is nothing inevitable about the link between poverty and failure. Indeed we have to ask ourselves why, if this is being done well in some places, it isn't being done everywhere else?
"We have to ask ourselves, if there is a political consensus on the importance of a sure start in life for all, if so much money is being spent on it, why on earth has so little changed?"
Last month, Sir Michael wrote to Ofsted's early years inspectors, urging them to focus on whether the provision they see prepares children for formal education, writing: "I want to know how well settings help children to catch up when they enter with skills that are lower than those typical for their age."
Sir Michael will also call for schools to take the lead in providing high quality early education, particularly targeted at youngsters from the most deprived backgrounds.
He is expected to say: "What children facing serious disadvantage need is high-quality, early education from the age of two delivered by skilled practitioners with degrees in a setting that parents can recognise and access easily. These already exist. They are called schools."
The report will argue for a simpler, more flexible and accountable early years system, to make it easier for parents to navigate the range of childcare options available and ensure they are getting the best provision for their children.
Speaking at Windrush Primary School in Greenwich, east London, yesterday - an "outstanding" rated school that provides both early years and primary school education - Sir Michael promised tougher inspections of early years providers and said teachers would be encouraged to "teach".
He also called on the Government to cut red tape to allow more schools to provide early years learning.
Sir Michael said: "The attainment gap between poor children and their more prosperous peers is large and if you are going to narrow it, it needs to start much earlier on.
"It needs to start before school starts, so therefore the early years provision has to be good. We are saying it isn't good enough, and we see better provision for poor children, where those gaps emerge, in school-based settings, and we are urging Government to put more early years settings into schools."
Sir Michael said Ofsted wanted a greater emphasis on teaching children core skills - "how to hold a pen... the ability to count, to recognise words, to communicate well with each other and their teachers".
He said: "If they don't have the basic skills, the social skills, emotional skills and learning skills that are necessary before four and five, they don't start school well and if they don't start school well they do badly in reception, they do badly at Key Stage 1 between five years of age and seven years of age, they don't read properly by the time they reach the SATs test at the age of seven.
"So this part of a child's career is absolutely critical, and we are saying that all providers should teach children those basic skills that they need in a very structured environment."
Children from poorer backgrounds often start school two or three years behind their peers from more prosperous backgrounds, Sir Michael said, a gap that has to be compensated for by teachers in the first year of primary school.
He said: "They do better in school-based provision - they do better in schools like this which have a discrete early years setting where they can teach these skills that are necessary to start school and can see these children progress from early years into reception and then in the early years of primary school as well.
"So we are saying we are going to be a lot tougher on early years settings which don't teach children these basic skills... w e want the Government to fund better provision, we also want the Government to remove the regulatory barriers that get in the way of primary schools wanting to open up nurseries."
Sir Michael denied that play and creativity would be sacrificed for learning, saying that pressure on children comes when they are not learning and are forced to catch up later on.
Ofsted inspections will be "toughened up", with a reduction in the number of inspection frameworks for early years learning to simplify it, ensuring children are not only properly cared for but adequately prepared for school.
Purnima Tanuku, head of the National Day Nurseries Association, rejected any suggestion that nurseries were failing children and challenged Sir Michael over the quality of Ofsted's inspection regime.
"You are missing the most important point here," she told him on BBC Radio 4's Today. "Your own report suggests that more than 80% of private and voluntary day nurseries are actually delivering good or outstanding quality.
"What is important is how we can invest in high quality and how can we create a level playing field.
"Most importantly, we should really be focusing on how to deliver quality inspections because there is a lot to be desired in the inspection processes."
She said there were only 335 schools accepting two-year-olds, "whereas 18,500 nurseries have been doing this and doing it extremely well".
"What Sir Michael seems to be saying is actually condemning the sector based on a very small minority.
"I'm not sure when (was) the last time Sir Michael set foot into a private or voluntary nursery, as opposed to a nursery school. He would see the high quality of play-based learning and a very suitable environment."