HUNDREDS of tonnes of debris have still not been removed from the Glasgow School of Art site one year after the fire that wrecked the world famous Mackintosh building, it has emerged.

The news comes as the investigation into that fire enters its final phases.

The historic landmark, designed by GSA alumna Charles Rennie Mackintosh, was extensively damaged when a fire broke out late on June 15 last year.

The flames burned so hot that metal struts bent and buckled.

They spread to the adjacent 02 ABC music venue, itself a well-loved cultural institution, destroying its famous roof and leaving it in an unsafe condition.

Meanwhile, residents of nearby homes were forced to evacuate as crews worked to extinguish the late night fire.

More than 120 firefighters took part in the operation, which happened as “the Mack” was nearing the end of a £35 million restoration ordered after the previous fire just four years earlier.

That incident prompted an emotional response from art and architecture lovers, while the second triggered questions about how it could have happened twice.

That is still unknown as investigations continue.

As many as 400 tonnes of fire debris have already been removed as two sectors of the building have been examined by fire inspectors. However, a “significant volume” is still there.

Yesterday Scottish Fire and Rescue Service (SFRS) group manager David Dourley said: “The investigation is progressing.

“We have already undertaken two examinations within the Glasgow School of Art and are now turning towards the final phases, which will be challenging due to the significant volume of debris which requires to be removed.”

Witnesses have been interviewed and hundreds of hours worth of CCTV footage examined during the investigation so far.

Earlier this year, Holyrood’s culture committee issued a damning report which said GSA bosses had failed to not properly safeguard the facility.

Yesterday SFRS assistant chief officer Ross Haggart said: “We are conscious that we are now approaching the one-year milestone of this devastating event that resonated not only here in Scotland but across the world.

“We are aware of the cultural significance of the Glasgow School of Art and the affection held for the O2 ABC alongside the impact on local businesses and residents who were affected at the time.

“This has been at the forefront of our minds throughout what has been a formidable investigation.”

Haggart continued: “The damage to the Mackintosh building was far greater than the fire incident in 2014 and the impact on the building has complicated the investigative process.

“Nonetheless, a number of detailed examinations at key areas of the site have been undertaken following the removal of 400 tonnes of fire debris.

“But a significant volume of fire debris remains within the site and we will work alongside the on-site contractors to have this removed with a view to undertaking further examinations.

“The fire investigation remains focused on likely origin and cause – but against the backdrop of an unprecedented large-scale fire scene within a complex and challenging site.

“Our fire investigation team is working hard based on what remains within the building once the debris is removed, alongside all other evidence available to them.”

GSA said: “We remain committed to bringing back the Mack as Mackintosh designed it for the benefit of our students, for Glasgow and for the wider world.”