Work will begin in March on building the new Oldfield School in Bray Road.
Secretary of State for communities and local government, Eric Pickles, rubber stamped the plans to go-ahead after they were approved by the Royal Borough in December.
The council says shrubbery clearing and archaeological digging will commence 'in the coming weeks', before construction of the 420 pupil school starts in March.
It is expected to be completed by March 2015.
The decision followed a lengthy dispute between parents and residents over the move.
Rising pupil numbers meant that Oldfield Primary School, which was recently named the ninth best primary school in the country, has outgrown its campus in Chiltern Road.
Critics have attacked the plans, as they involve building on greenbelt and floodplain land.
The site was unaffected by the flooding which blighted much of the Royal Borough since Saturday.
Richard Jarrett, headteacher at Oldfield, said: "We are absolutely delighted."
"It means the school community can now move forward and plan for the future."
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