So the UK's intelligence chief warns of 30 terrorist plots in the works against them, and on the same day, the former head of the Ministry of Defence's UFO division warns of impending attacks from aliens. What should we be more worried about?!

From the BBC:
MI5 tracking '30 UK terror plots'
Eliza Manningham-Buller rarely speaks in public
MI5 knows of 30 terror plots threatening the UK and is keeping 1,600 individuals under surveillance, the security service's head has said.

Dame Eliza Manningham-Buller warned the threat was "serious" and "growing".

She said future attacks could be chemical or nuclear and that many of the plots were linked to al-Qaeda.

Prime Minister Tony Blair said the terrorist threat was "very real" and spoke of "poisonous propaganda" warping the minds of young people.
From The Daily Mail:
'Aliens could attack at any time' warns former MoD chief
UFO sightings and alien visitors tend to be solely the reserve of sci-fi movies.

So when a former MoD chief warns that the country could be attacked by extraterrestrials at any time, you may be forgiven for feeling a little alarmed.