A medieval barn described by the poet John Betjeman as the ‘cathedral of Middlesex’ has been rescued from decay and neglect for the nation, English Heritage said today.

Grade I-listed Harmondsworth Barn in west London joins the likes of Stonehenge, Osborne House and parts of Hadrian's Wall in the national collection of historic sites and monuments under the guardianship of English Heritage.

Built by Winchester College in 1426, the barn would have been used to store grain from the surrounding manor, owned by the Bishop of Winchester, with profits from the produce used to pay for the school....