The correct distinction to be made in this debate is the distinction between the content and the medium.
Some of us are old enough to remember the same argument about taping stuff off the radio, and a call for a tax on C60/C90 tapes.
Some of us even remember C75 tapes which were conveniently just long enough to fit a whole LP on
and before that, people who didn't like the critical or heretical views in printed material decided to smash these new printing presses. Mistaking content with the means of distribution.
To be quite clear, the Rights protected by Copyright include the right of the creator of an original work to give it away for free, and any measures to restrict distribution must accommodate that right. As a trivial example, we can remember that the music to "Happy Birthday" is still within the term of its Copyright, but there is no claim by the Rights owners for revenue from its performance, so it may be performed without payment of a Royalty. (There are royalties collected from the recording and copying of recordings of "Happy Birthday" and the Rights owners will be credited at the end of any film which includes the song.). This is because the Rights owners choose not to claim their Rights, it has nothing to do with how or where it may be performed, nor the medium though which it is copied, distributed sold or broadcast.
Any retrospective measure to 'plug the gap' such as imposing a levy on blank cassette tape, CDRs or downlod sites will always fail in its intentions when tested against examples of material which is still within its terms of Copyright but which the owners wish to disseminate for free (talking books and recordings of one's friends and family being other popular examples).
Having made that distinction and agreed that the concern is one of Intellectual Property Rights (IP) and not one of any specific medium of supply, then the next port of call should be to an IP Lawyer and not to a Computer Expert!
The Music and Film Industry bodies representing the rights owners have been very active in the last few years, and quite rightly too; the most recent report on the matter was the
Hargreaves Report which, although not universally accepted, studied the main models of revenue earning capability which the industries could adopt and which sustain the revenue earning capacity of IP rights holders.
Acknowledging the massive contribution that the Creative Industries make to the UK economy, the matter of IP Rights is also of interest to the Government and you'll easily find debates and papers published on the matter exercising the minds of these industries' representative bodies as well as DCMS.
Frankly, the biggest areas of concern are not Torrents but the inconsistency in Rights legislation around the world. We can find products being copied and sold from one territory into another where the Royalty Collection mechanisms are not in place to collect and distribute the fees due to the original creators and their producers.