This Was an Easy Decision to Intervene

British authorities had been watching the airplane-bomb conspirators for month, biding their time until they got as much information about the group as possible. This was a reasonable risk-management decision, of course.

The Australian has reported that the decision to intervene came as a slam-dunk, essentially:

"GO now!" The message came from Pakistan and it rattled the British intelligence agents who intercepted it.

The urgent direction was sent early this week to a group of young British Muslims who had been plotting one of the world's biggest-ever terrorist attacks.

Intelligence officials who had been monitoring the group thought they had plenty of time to keep watching them and gathering evidence before safely rounding them up early enough to stop them carrying out their scheme.

But the message from radicals in Pakistan saying "do the attacks now" changed everything, and when it was passed to higher authorities in London on Wednesday night, it sent a jolt through the top levels of the British Government.

Normally, the decision to intervene would be a little more complex, as it would occur earlier in the process. It's risky to wait until an attack is imminent.