Firefighters spent all night tackling a blaze at an industrial unit in Lancing.
The building, believed to be used for manufacturing furniture, was well alight when fire crews arrived at Lancing Business Park in Peter Road at about 7.45pm on Saturday.
The firefighters tried to douse the flames from above using an aerial ladder.
Two firefighters had gone into the building but had to leave before the roof collapsed.
No-one was injured in the blaze and no-one was reported to have been inside when it started.
The cause of the fire is still unknown. Fire investigators and police scenes of crime officers are expected to begin their inquiry this morning.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article