Code Nine

Code Nine was a priority alarm initiated when computer software - activated on the release of the Emergency Protocols - detected important words.

When Jackie Tyler phoned the BBC alien helpline and told them about the Doctor and his TARDIS, the words were highlighted and a Code Nine was declared. Indra Ganesh informed General Asquith of this development but he did not understand as he was in fact a Slitheen, impersonating the General. (DW: Aliens of London)