The world’s largest glasshouse, the Grade 1 listed Temperate House at the Royal Botanic Gardens, Kew, is open to the public again after a five year, multi-million-pound restoration.

The Victorian glasshouse, first opened in 1863, had deteriorated to such an extent that by 2012 a survey found it was in a state of disrepair and should be closed. Kew decided to embark on the largest restoration project in its history, erecting scaffolding equivalent to the length of the M25 around the building and painstakingly returning the glass, iron structure, ventilation systems and paths to their original splendour. The £41 million cost was met by Kew with help from the Heritage Lottery Fund and government funding, as well as private donors.

About 500 of the 10,000 plants which live in the glasshouse were moved to alternative accommodation during the work, with many more propagated ready for replanting in the finished glasshouse. Some plants did not survive the upheaval including its most famous inhabitant, a 19m (62ft) tall Jubaea chilensis grown from seed in 1846 and the largest glasshouse plant in the world. Luckily Kew had already taken cuttings, and its offspring are now growing in its place.

The newly-restored glasshouse continues to shelter some of the world’s rarest and most threatened plants. They include the cycad Encephalartos woodii, known as the loneliest tree in the world as all the female specimens have died out to leave only males. And Kew’s Temperate House is the only place where the flowering tree Dombeya mauritiana grows in cultivation; it was thought extinct until a single specimen was found in the highlands of Mauritius.

Sir David Attenborough, who officially reopened the Temperate House, said he was ‘delighted’ with the restoration.

‘It is a breathtakingly beautiful space,’ he said. ‘These plants are wonderful, and here they are safe from peril.’