During the brief time that the Senate was in lockdown during an incident which saw shots fired, security used the new Twitter Alert to make sure those inside the building had the most recent and reliable information:
The new system was unveiled by Twitter last week as a more effective way to highlight critical information for users.
More top news
It has a wingspan of 79ft and can fly non-stop for more than 40 hours.
Full blown blue skies
David Lidington warned that Brussels institutions could be putting their own citizens at greater risk of attack.