Around 900 people were evacuated from Western Europe's tallest building as firefighters investigated reports of smoke.
London Fire Brigade said there was no evidence of a fire in the 1,004ft Shard, near London Bridge, adding that the smoke was dissipating.
A spokesman said the whole building was evacuated as a precaution and n o injuries had been reported.
He said the presence of seven fire engines and around 50 firefighters was usual for that type of building.
Scotland Yard said no arrests had been made and i nquiries were going on into the source of the smoke.
London Ambulance Service was also called out but said "there are no patients".