There are weeping willows drifting over lakes covered in Asian waterlilies, walled gardens overflowing with pastel-coloured flowers from South America, and tree-lined pathways leading to woods drunk on wild violets. Dotted everywhere are UNESCO-preserved buildings filled with hothouse flowers and pretty cafes.

And there is now more reason to go, as the jewel in Kew Garden’s crown has recently reopened after a serious makeover. The breathtakingly beautiful Temperate House has had a £41 million (HK$413 million) refurbishment and has regained its place as one of the most extraordinary buildings in London.

Designed by Decimus Burton in 1860, it has been the largest glasshouse in the world since its construction. Walking inside, it is difficult to know what to marvel at first – the imposing Victorian structure or the other-worldly plants that reach precariously towards the glass roof.

The refurbishment took five years, with 10,000 plants uprooted and replanted, 15,000 panes of glass replaced and 69,000 sections of metal, stone and timber repaired. There was enough scaffolding to stretch from Hong Kong to Macau three times over and more than 1,000 people working on the project. Light now floods into the glasshouse, partly because the tallest plants, which were brushing the ridge of the roof, have been pruned or replaced with shorter specimens.

Several of the plants in here are part of international conservation projects to preserve or reintroduce them in the wild. One is the South African cycad Encephalartos woodii, also known as the ‘loneliest tree in the world’. A survivor from the time of the dinosaurs, it is now extinct in the wild, and only this male specimen – a clone of the tree which arrived at Kew Gardens in 1899 – remains. Unless a female is found, it will never reproduce naturally.