The ITV newsroom was evacuated during a live programme after a fire alarm went off.
Tom Bradby was presenting the 10pm news on Wednesday and told viewers that they had no choice but to leave the building.
"As you can probably tell we have a fire alarm - we're not quite sure what to do about it," he said.
"I'm really, really sorry about this but I'm afraid we have to evacuate the building. These things happen and unfortunately it has happened tonight and we have very little choice.
"I really apologise, we will get back to you with the rest of the programme if we possibly can."
ITV later said it was a false alarm and that all staff were safe.
Head of communications Laura Brander tweeted: "Just spoken to @tombradby live from the scene of the @itvnews fire drill & can confirm thankfully it was a false alarm & all staff members are safe & well."
Presenter Alastair Stewart tweeted: "Blimey. Fire alarm disrupts then stops @itvnews at Ten. Calmly handled by @tombradby."
Newsreader Kylie Pentelow posted: "Fire alarm @itvnews takes #NewsatTen off air..."