The fire has now been put out. Fire crews will remain on site damping down the blaze.
Around 70% of the building has been destroyed and electricity supplies have been cut off for safety purposes.
The cause of the fire is not yet known.
More top news
Overcast and dull, with hill fog and outbreaks of rain throughout the day.
It will be a dull, damp and cloudy day for most, with outbreaks of rain. The rain will start to ease from the west during the evening.
Cloudy this evening and overnight, with mist and hill fog becoming widespread.