Derbyshire Fire and Rescue received a number of calls around 3.30pm today after reports of an explosion at a disused Thornton's factory in Belper.
People were reported to be inside the building at the time of the explosion but everyone is accounted for.
Fire crews are now damping down and the fire is under control.
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It will be a breezy, but still a rather cloudy day across the region with intermittent drizzle possible.
Remaining cloudy but with a freshening southeasterly breeze helping to clear much of the mist and hill fog.
Another cloudy and murky night with extensive low cloud giving hill fog and some patchy light rain or drizzle.