HUNDREDS of pupils have not returned to school this week as building work delays the start of the new term.
Four schools in Croydon have been unable to open as planned because new buildings are not ready.
A fifth was facing a race against time to open next week after its temporary classrooms were delivered late.
Expansion work took place at 17 schools across the borough this summer as part of efforts to meet unprecedented demand for places.
As many as 1,500 pupils were unable to go to school this week as a result of the delays.
The council said its expansion plans had mostly gone to plan with the affected schools only closed for "one or two days".
Those unable to open will have to make up the time over the coming school year.
The schools in question are Quest Academy, in Farnborough Road, South Croydon; Norbury Manor Primary, in Abingdon Road, Norbury, and Parish Church junior and infant schools in Warrington Road, Croydon.
The new free school in London Road run by the Harris Federation, a building project overseen by the government, did not open on time either.
Quest Academy, which has around 520 pupils on roll, will return five days late because their new £16 million school building is not ready.
The new term was due to start on today (September 4) but has now been pushed back a week to September 11.
Principal Andy Crofts said the delayed opening was the result of heavy rainfall in January, which set back building work, undertaken by contractor Wates, by four weeks.
"Remarkably Wates were able to recoup three of these weeks resulting in just the one week delay," he explained.
"It was not possibly to open in our old building because it has been stripped ready for demolition, however staff are in this week in just four rooms preparing for the new term.
"Rather than in anyway a chaotic start to the term we made a decision to open a week later."
Thirty hours of school time have been lost because of the delay, which will be recovered by students staying back for an hour longer for 30 of the 39 school weeks this year.
Mr Crofts said: "The time lost will be made up in the course of the year so obviously the children do not suffer any detriment.
"Everyone is looking forward to enjoying fantastic new facilities next week."
Last week, the Advertiser revealed the opening of Harris Invictus Academy, a free school on the former site of Croydon General Hospital in London Road, had been delayed by a week because of problems with the temporary buildings it will be based in.
The secondary school, linked to the Harris Federation, will be housed in temporary classrooms until its permanent buildings are finished in 2016.
It was due to open today (Thursday) but that was pushed back until September 9 because of a delay in bringing the temporary buildings to Croydon from the Midlands where they are being made.
Those buildings have now arrived and the site was being prepared this week.
The council, which is not responsible for free schools, said it is in contact with the Education Funding Agency (EFA), the government department in charge of the building work, to ensure the site is safe and cleared before its first 164-pupil intake arrive.
The EFA has not responded to requests for a comment about the delays.
Neither Norbury Manor, which has been expanded to three forms of entry, or Parish Church schools had commented as the Advertiser went to press on Thursday.
The council said the schools had asked for "an extra day or so" to make preparations before they opened.
"The summer holidays is an extremely busy period within the schools expansion project, as the schools are not in session," a spokesman said.
"However, having the new space completely ready for the children is important so where a small number of schools have asked for an extra day or so to make these preparations, the council has been supportive - provided parents are also supportive and there are plans in place to deliver the full number of required curriculum hours for the children."
Maria Gatland, shadow cabinet member for education, said delays were the inevitable result of trying to meet the huge demand for places, especially at primary school level.
"I think opening a couple of days late is fine as long as it doesn't impact on the curriculum. That's clearly the most important thing," she said.
The majority of schools involved in the expansion programme have not experienced delays, including the new annex in Brigstock Road, Thornton Heath, run by the Pegasus Academy Trust. Pupils are also due to start at Harris Primary Academy Haling Park, in South Croydon, next week.