More than 100 firefighters have been tackling a blaze at a mill complex used as a film location for hit shows such as Peaky Blinders and Downton Abbey.
Fire crews were drafted in to tackle the inferno at Dalton Mills in Dalton Lane, Keighley, West Yorkshire.
West Yorkshire Fire and Rescue Service said 20 pumps were called out just before noon.
The service said the incident was being scaled back but some crews would remain overnight to damp down the blaze.
People living nearby were earlier told to keep windows and doors closed and to avoid travelling through the area because of the smoke.
There is a police cordon in place and some roads have been closed.
Nick Smith from West Yorkshire Fire and Rescue Service said nobody had been hurt in the fire. He described dealing with the blaze as "challenging".
"Internally the building has collapsed, the floor and the roof," he said.
Mr Smith said the incident was being scaled back, but firefighters would spend the night damping down the fire.
The fire service said appliances from neighbouring brigades were also in attendance, along with police, ambulances, Yorkshire Water and the Environment Agency.
One eyewitness, Gary Coates told BBC Radio Leeds: "As we passed there was smoke coming out and then we started seeing flames coming from the bottom floor of the mill.
"Within minutes it was an inferno. It was really bad. It was intense, flames coming out from everywhere.
"We could feel the heat from where we were parked, perhaps 200 or 300 yards away."
The mill had been used for a number of film and television production in recent years.
Richard Knight, from Screen Yorkshire, described the fire as "a sad loss to the Yorkshire film-making landscape".
"It's one of those amazing locations that is like a destination in its own right," he said.
"It's got the kind of provenance and scale that could attract film-makers from far and wide."
As well as Peaky Blinders and Downton Abbey he said part of the site had been transformed into London's Victorian-era East End for the 2016 film The Limehouse Golem, starring Bill Nighy.
The Victorian building, constructed in 1869, was once said to be the largest textile mill in Yorkshire, employing more than 2,000 workers.
It fell into disrepair before being partially restored and taken off English Heritage's at-risk register in 2015.
The complex was previously struck by a serious fire in 2011, when it was believed copper thieves set fire to the site as they tried to burn off insulation to steal metal.