The Department for Education says that the new school - Bohunt Horsham being built on land north of the town - will open in December next year.
The school, which will provide places for 1,620 children aged from 4-16 plus a 50-place nursery, is being built as part of a massive new 2,750-home estate on land off the A264.
Originally, it had been planned to open the school this year but delays to building of the whole estate because of the coronavirus pandemic mean it is now intended to open in December 2021.
The Department for Education says that building works on the school, which is being run by the Bohunt Education Trust, are scheduled to begin ‘in earnest’ this September.
Bohunt Horsham currently has temporary accommodation in Hurst Road, Horsham. Headteacher Georgette Ayling said: “After a lot of discussion and some rapid conservation work, despite the uncertain times, we now have a building handover date for our exciting new-build school.
“The complexities of land ownership, wildlife surveys and Covid-19 have made deciding timelines very difficult.
“However, a phased handover means that we are booked in to move to the secondary part of the site, complete with safe outdoor sports and social spaces and a fully functioning sports hall, from December 2021.
“The rest of the site is due for completion by Easter 2022.
“Our current school site will continue to provide an excellent home for our community during the next academic year, after which additional classrooms will be located very close to the current site, giving us the space we need to take, as planned, a full year group of 240 students in September 2021.”
She added: “Having dates in the diary, albeit with a period of uncertain time to negotiate until handover, is hugely reassuring.
“However, what makes our school such a great place to learn and work is not the building, but the culture, the ethos and the brilliant people that make up our community.
“Our students, staff and our families have made this year a huge success, and it gives me enormous pride to know we will continue on this road next year, as we wait just a little longer than we were expecting for our amazing new site.”
Legal & General, which owns the site north of Horsham, revealed in May that plans for the whole estate were behind schedule because of the Covid pandemic.