BBC Radio 2 fell silent for the first time in two decades as a fire alarm prompted an evacuation in the London building on Thursday, 6 March.
Jeremy Vine's show was interrupted by the alarm before employees in Broadcasting House filed outside while it was investigated.
Apologising for the disruption, the host explained the silence.
"We did just have a proper fire alarm here," Mr Vine said.
"There wasn't a fire but we had the thing that I've not had in 20 years where not just one light goes off but two."
