The extent of damage to the Glasgow School of Art, following a devastating fire last week, has been revealed in drone footage of the wreckage.

Glasgow School of Art released a video shot using a drone showing the damage to the Charles Rennie Mackintosh-designed building, after a visit to the site on Monday 18th June.

The seminal building by Scottish architect Mackintosh was destroyed by a large fire that began on Friday 15th June. The building was in the process of being restored following a fire that severely damaged the building four years ago.

According to experts the latest fire has damaged the building beyond repair, with the cost of rebuilding the school of art estimated to be £100 million. This latest footage reveals the full extent of damage to the building, which was completed in 1909.

"Huge desire to see Mackintosh's masterpiece rise again"

The footage was collected by staff from the Glasgow School of Art's School of Simulation and Visualisation, who visited the site along with experts from Glasgow City Council, Historic Environment Scotland and structural engineer David Narro Associates, to begin assessing the damage to the building.

Along with the footage, the team took detailed photography and made 3D-visualisations of the damage, as the first stage in determining the future of the the building.

"This was the first opportunity for the expert team to see the building and begin what will be a long and complex process of determining the future of the Mack, but we remain optimistic." said Tom Inns, director of the Glasgow School of Art.

"There is a huge desire to see Mackintosh's masterpiece rise again, one which we all share," continued Inns.

"We have incredibly detailed information on the building collated over the last four years, and have worked with teams of talented craftspeople, who were doing a tremendous job on the restoration."

"Complex and thorough" fire investigation begins

The Scottish Fire and Rescue Service (SFRS) has begun the official investigation into the cause of the fire.

"Our fire investigation team has started gathering information and, working alongside our police partners, will look at various sources of information to establish exactly what has happened here," said David McGown, assistant chief officer of the SFRS.

The investigation will be "complex and thorough", and is expected to take a considerable amount of time said the service.

"[The fire investigations team] will look at every aspect of this incident – including the cause of the fire, how it spread and what safety measures were in place," continued McGown.

"We understand the need for clarity here and why so many want to know how this happened, but I would again like to reiterate that we need to establish the full facts and circumstances of this incident – and this will take time."

The Glasgow School of Art is the best-known building designed by Mackintosh, Scotland's most famous architect. The 150th anniversary of the architect's birth took place earlier this month and Dezeen published a special series to mark the occasion.