BBC World Service, this is Helen Merriman with the inquiry.

This week, the drone strikes work.

It's 7 a.m. on Monday the 7th of September, Pakistan.

Aseim Badjoa, a three-star general in the Pakistani army is composing a tweet.

First ever use of Pac-Made Barak drone today, he writes, hit a terrorist compound in

Chawell Valley, killing three high-profile terrorists. Details follow.

It's not long before its headline news.

For the first time in its history, Pakistan has used an unmanned aircraft to kill militants. In doing so, it's joined a select club. Only three other

countries have carried out drone strikes, the US, theK. and Israel.

But this could soon change.

According to an American study, 90 countries are now operating drones,

and 30 of them plan to arm them.

Armed drones then, it seems, are becoming today's counter-terrorism weapon of choice,

a weapon that's raised complex legal and ethical questions.

But today we're interested in a more basic one.

Just how effective a drone strikes in the fight against terrorism. In short, do they work?

Now before you meet our first expert witness, we're going to introduce a piece of

evidence to this inquiry. It's a 20-page document, the American National Strategy for Counterterrorism. It sets out a series

of goals and it's going to form the backbone of this inquiry. Since drone strikes have become

a pillar of American counter-terrorism efforts,

we're going to judge the effectiveness of drone strikes by looking at whether they've helped the US achieve its aims.

Of course, no one would claim that drone strikes are the sole strategy for meeting all of these goals,

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