Lambeth Police have confirmed that the security incident at St Thomas' Hospital has been stood down.
Their statement comes less than half an hour after it was announced that the police had been brought in to handle what was described as a "security alert".
The hospital has yet to make any comment.
Eyewitnesses report that half a dozen police cars have surrounded the hospital and patients, nurses and doctors are being blocked from entering the building.
The Metropolitan Police stated there were no reports of injuries during the incident, which saw members of the public evacuated from the surrounding area.