Proposals for a £70m overhaul of Edinburgh's Royal Botanic Gardens have been approved.

The plans have been labelled "the most significant project in the gardens' history".

A new curved glasshouse, 20m in height, will be built with a multi-level walkway to house a "wider range of plant specimens", as well as a new visitor attraction.

The current education building will be replaced with a new structure while a new research glasshouse will replace the existing range of interconnecting research glasshouses.  Existing greenhouses are set to be upgraded with double-glazing.

A separate application to build a new sustainable energy centre and 'plant health suite' at the gardens' nursery site, north of the public area, was also approved by councillors.

The technology, only matched in the UK by Kew Gardens, will use a combination of ground-source heat pumps, combined heat and power engines and gas boilers to produce both heat and electricity to the main gardens attraction and greenhouses.

RBGE regius keeper Simon Milne said: "As a world-leading botanic garden responding to the climate emergency and the associated alarming loss of biodiversity, we recognise this is an essential, urgent and exciting project of national and international significance, bringing great benefits to society.

"It is a necessity to avoid the catastrophic loss of up to 4000 species in our collection.

"The planning decision enables us to move forward with what is the most significant project in the gardens' history. The need for our pioneering work has never been greater, be it through cutting-edge science, impactful education or inspiring people with the beauty and value of natural capital."

By local democracy reporter David Bol