It is all a big waste of time
I spent some time going working with a network attached anti virus device that would scan all traffic coming through it for potential virus' and various malware.
The idea was brilliant, but there was one glaring little hole that didn't get mentioned much.... SSL.
Any data that came through an SSL connection was encrypted so we couldn't scan it to see if it contained malware unless we decrypted it first. It is possible to decrypt data, but it takes time and effort and is not feasible to do to all traffic so anything that came through SSL was ignored.
I would suggest that if this ever takes off everybody will just start using encrypted connections. The ISP's could log it, but it would be bloody meaningless to anybody unless they sat there for a few years decrypting it all (512bit encryption takes a while to break through and everybody can have it nowadays).
After randomly trying to go through a few peoples data and coming up with nothing they will probably give up dur to the prohibitive cost. Or they will demand the ISP's decrypt the data as well and watch them all go out of business....
Another well thought out idea by the Home Office.....