The government has committed £17m to help an inner London primary school to offer its pupils free places at a new state boarding school in Sussex.
Students from the Durand Academy in Lambeth would stay at the secondary school in Sussex from Monday to Friday.
The trust running the primary school bought the 20-acre Sussex school site for £3.4m last year, using income from a gym and flats on its London site.
It comes as Lambeth council is struggling to provide primary places.
Durand Academy, which has a high proportion of pupils on free school meals, plans to open a new junior school on its site in Stockwell, south London, in 2012.
It also hopes to open a boarding school in Sussex, which students would attend from the age of 13, in 2014.
Under the plan, pupils would be driven out to the leafy Sussex site on Monday morning, and return on Friday afternoon.
A trust connected to the school manages the income from a gym and some flats on its London site, and says it will pay for the construction of the junior school and accommodation for sixth form boarders, as well as the boarding costs of pupils.
The Department for Education's £17.34m, which will be spread over four years, will fund the construction of the boarding school's main teaching and accommodation building.
Durand Academy head teacher Greg Martin said the project would "transform life opportunities for children and families from Stockwell's estates".
"We will offer an extended school day combining academic rigour with music, drama and sports in a rural environment," he said.
The school says it also hopes to gain some income from use of the boarding school's sports facilities and grounds, and rentals of its premises during school holidays.
The Department for Education said the money came from a portion of the schools capital budget dedicated to "policy priorities" such as free schools and academies.
Schools capital funding as a whole is being cut by 60% between 2010-11 and 2014-5.
"The poorest children are too often left behind because of weak schools and lack of opportunity. This unique and pioneering project, led by one of London's best primary schools, will give disadvantaged pupils the type of education previously reserved for the rich," a DfE spokesman said.
It comes days after Lambeth Council warned that it could not guarantee a primary school place for every child in the borough by 2015.
It is calling on parents to back its plea to the government for £50m additional funding over the next two years, on top of £56m it has received since 2006.
Without this extra funding, it warned it would have to cram more classes onto school sites "already full to the brim".
The Department for Education (DfE) has given £800m to local authorities for additional places for 2011/12.