Update 16:48. London Fire Brigade now believes no one is trapped but at least four people have been injured.
Original article below
London Fire Brigade has been called to the Mango store on Oxford Street following reports of collapsed hoarding.
Eyewitness reports on Twitter suggest several people were caught underneath, and there is some talk of injuries. Other emergency services are in attendance. The road is currently closed in both directions.
More news as we get it.