Victorian Conservatory, Wentworth Castle Gardens

In 1885 Thomas Vernon-Wentworth inherited Wentworth Castle in Yorkshire, together with a fortune of close to £1 million. He soon had a large ornamental conservatory built in the gardens to show off the exotic plants — orchids, palms and ferns — that the family had gathered from around the world. The commission went to Crompton & Fawkes of Chelmsford, who designed, erected, heated and lit the building; the firm called it an "iron winter garden" and gave it pride of place in its 1899 catalogue.

Through the twentieth century the structure slowly decayed. Placed on the Buildings at Risk register, it appeared on the BBC's Restoration series in 2003 but failed to win the public vote, and in 2005 it had to be shored up with scaffolding to stop it collapsing. Funding of about £3.7 million was secured in 2011 from English Heritage, the Country Houses Foundation, the Heritage Lottery Fund and the European Regional Development Fund. Work began in 2012 and was finished in October 2013; the Mayor of Barnsley opened the conservatory on 7 November 2013 and the public were admitted the next day, the building now serving as the gateway to the World at Wentworth project. Since June 2019 the gardens have been run by the National Trust in partnership with Northern College and Barnsley Council.

Listed Grade II*, the building combines iron and glass on the ridge-and-furrow principle, the zigzag roof profile typical of Victorian glasshouses. The floor is laid with geometrically patterned tiles, beneath which ran an elaborate heating system, steam-powered and supplied by Crompton. The conservatory was technically advanced in another respect too: it had electric lighting by 1886, making it one of the first places in Britain to be lit this way, ahead of Buckingham Palace.

For the restoration, Shepley Engineers surveyed, tagged and dismantled every component and took the structure to its Barnsley workshop. Wrought and cast iron that could be kept was repaired, while new wrought-iron glazing bars, cast-iron gutters, shoes and columns were made, along with new window, door and roof units. Roof bays were trial-assembled in the workshop before painting, after which the whole frame was taken back to the site and re-erected.

Period accounts describe a house filled with palms, tree ferns and other ferns, begonias, orange and lime trees, a Norfolk Island pine and several climbers, including a hybrid passion flower and Cobaea scandens, with passifloras trained across the roof.

Today the National Trust displays plants from five continents, chosen so that something is always in flower whatever the season; in summer the bird-of-paradise blooms are among the highlights. The conservatory also houses an interpretation display on the statue known as The Kneeling Man, which addresses the Wentworth family's connections with the slave trade.

The conservatory acts as the arrival point for Wentworth Castle Gardens at Stainborough, near Barnsley. The estate holds three National Collections — Camellia x williamsii, magnolias and species rhododendrons — which are at their peak from late February to early July, together with a striking show of azaleas. A visit can take in Stainborough Castle, an early eighteenth-century folly whose surviving tower gives wide views, the Union Jack Garden with its hedges laid out in the pattern of the flag, and the Sun Monument, a rotunda dedicated to Lady Mary Montagu. Half a day covers the whole estate comfortably.