Fire crews tackled a fierce blaze in the roof of a four-storey building in the centre of Norwich.
The fire took hold in the building off Fishergate by the river.
Fire crews have cordoned off the street while they fight the flames.
Crowds gathered to watch as crews from Carrow, Sprowston, Earlham, Hethersett, Loddon, Wymondham, Dereham, Gt Yarmouth and Gorleston tackled the flames.
Onlookers said they thought the whole roof had collapsed.
The fire service confirmed that all persons within the buildings had beenaccounted for, and said that while the fire was still being attended, there wasno risk of it spreading.
"The flames were huge, not something you expect to see. It all took hold so incredibly quickly. Then the blocks of flats next door were evacuated, I think. Amazing work from fire crews and emergency services."