Teachers and pupils have been based at The Winslow Centre for two-and-a-half years while councillors and developers wrangled over details.
But an agreement has now been reached to create modern classrooms in a new three-storey building which the free school can call its own.
It means pupil numbers will be boosted from 283 to 600, including Sixth Form students, while groups and societies will be able to return to The Winslow Centre.
Headteacher Darren Lyon said: “The biggest thing is that we’ll now be in a purpose-built school. We have been making do with a building which isn’t fit for purpose - it’s a massive relief.
“I would like to think that children will now choose our school because it’s their local school.
“It offers everything they need, we cater for all abilities. We want children to think it’s the right place for them, not just because they haven’t passed the 11+.”
Llew Monger, Aylesbury Vale District Councillor for Winslow, said the delays were because ‘pre-application advice was ignored’ but he is looking forward to seeing the results of the £10 million build.
He said: “It will be great for young people here to attend a newly-built facility. And hopefully it means more and more Winslow children will be attending so it becomes ‘the’ school for Winslow children.”
Delays to securing the site and the discovery of a high-pressure gas main running close to it, meant the planning approval was pushed back.
And a parallel application for access roads which includes the new railway station, submitted by different developers, caused further complications. But the two applications were separated and building work, by Keir Construction, can now go ahead.
The plans include creating a multi-use games area, a car park, coach park and cycle racks. It is scheduled to take just under a year to complete the work.