Fire crews from the London Fire brigade raced to the Communication Tower on Cleveland Mews following reports of smoke issuing and an automatic fire alarm sounding from the grade two listed building.
A number of appliances and officers were scrambled to the iconic site at around 8.30am on Wednesday morning.
The cause of the alarm and smoke is under investigation.
A spokesperson for the LFB said: Firefighters were called to a fire alarm sounding and reports of smoke issuing at the BT Tower on Cleveland Mews this morning (Wednesday).
It was a false alarm. The Brigade was called at 8.15am and the incident was over for firefighters by 8.27am