About 200 school-based nurseries will open in England this September as part of the government's plan to improve access to childcare for working parents.
The milestone will be announced on Monday by Bridget Phillipson, the education secretary, who will say that the sites will accommodate 4,000 children under school age.
A further wave of school-based nurseries will launch in the autumn, taking the total to 300, adding to other measures aimed at helping parents such as free breakfast clubs, more free hours of childcare, an expansion of free school meals and a cap on school uniform costs.
Phillipson said: "Every corner of the early years sector has a vital role to play, and the progress made so far, in the face of an enormous inherited delivery challenge, is testament to their dedication to children and families up and down the country.
"This September is only the beginning. This government has a clear plan for change to get tens of thousands more children school ready each year so that every child, from any background, gets the opportunities they need to get on in life."
Phillipson first announced the plan just before the Labour party conference last year, saying 300 sites would be open within 12 months.
The government said the 200 sites getting ready to open were exceeding the number of places they thought they could offer, with 4,000 projected.
Phillipson said the schools were chosen in places currently underserved by the market. There will be an average of 20 places for each site and up to 6,000 new places when the programme is complete.
The government believes that 30 funded hours of childcare a week will save parents up to GBP7,500 on average, while GBP450 a year will be saved through free breakfast clubs in schools.
Last month, the government announced almost GBP370m of further funding to support the future of the programme. Some of the sites involve the conversion of empty classrooms into early years settings.
Wayne Wathen-Howell, the headteacher of Minet infant and nursery school in Hayes, said: "We're proud to be opening a new nursery right here in our school - it's a big moment for our community.
"Parents have told us how important it is to have affordable, high-quality childcare close to home, and this new nursery will make a real difference. Not only will it help families balance work and family life, it also gives our youngest children the best possible start in a familiar, supportive environment."
Source: The Guardian