English Heritage has announced that it has secured the future of the Grade I Harmondsworth Barn in west London.
The late poet laureate, Sir John Betjeman, dubbed the building "the cathedral of Middlesex".
Before its restoration, the barn - built in 1426 by Winchester College and used to store grain - had fallen prey to years of neglect and decay.
The barn, which will be open to the public in April, will be run by and for the local community.
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