This major overhaul of the Grade-I listed Temperate House, dating from 1863, involves the replacement of all glass panels and repainting of struts.

While the full restoration project is expected to cost £34m, the structural and glazing work is expected to come in around £20m.

Kew botanists started carefully removing the rare plants from the decaying building last year to allow work to start on the three-year restoration job.

The Temperate House encloses an area of around 4 000 sqm and was last restored in the late 1970’s. It was placed on the English Heritage Buildings at Risk register in 2012.

When the Temperate House reopens the familiar white colour scheme from the 70s will be replaced by a variety of colours including sky blue identified from paint scrapes.

Each of the more than 100,000 glass panes will be removed and cleaned or replaced. There will be better disabled access, along with a new education centre.