Armed police carried out a search after closing down Bank and Liverpool Street stations. The two stations reopened just after 7pm.
Commuters were evacuated causing travel chaos with one calling the ordeal "terrifying".
Evacuated off central line train at Bank by armed police, terrifying. Hope no ones hurt!— Catriona Toogood (@CatGray1) December 14, 2016
British Transport Police said it received reports "about a man with a knife at Bank station" at 5.11pm.
"As a result trains were stopped at Bank and Liverpool Street stations," BTP said.
"Liverpool Street and Bank stations were searched by officers with no trace of the man.
"Enquires are on-going and officers are still on the scene."