Nancy Gish wrote:
 > British copyright law (I learned when editing the TSE book) is quite
 > different from US law.  Ours is based on the percentage of a text that
 > is quoted.

That is only one of the considerations in the U.S.

I'm not advocating using Wikipedia for legal advice but it can be useful
in getting an understanding of what might get you into trouble before
you do something you'd be sorry for.  See their articles on "Fair use"
and "Fair dealing"

Wikipedia quotes U.S. law:

[Fair use under United States law] only existed in the U.S. as common
law until it was incorporated into the Copyright Act of 1976, 17 U.S.C.
 107, reprinted here: 

Notwithstanding the provisions of sections 17 U.S.C.  106 and 17 U.S.C.
 106A, the fair use of a copyrighted work, including such use by
reproduction in copies or phonorecords or by any other means specified
by that section, for purposes such as criticism, comment, news
reporting, teaching (including multiple copies for classroom use),
scholarship, or research, is not an infringement of copyright. In
determining whether the use made of a work in any particular case is a
fair use the factors to be considered shall include:
        1. the purpose and character of the use, including whether
           such use is of a commercial nature or is for nonprofit
           educational purposes;
        2. the nature of the copyrighted work;
        3. the amount and substantiality of the portion used in
           relation to the copyrighted work as a whole; and
        4. the effect of the use upon the potential market for
           or value of the copyrighted work.
The fact that a work is unpublished shall not itself bar a finding of
fair use if such finding is made upon consideration of all the above


The Wikipedia article explores each of the provisions with examples of
effective fair use defence against copyright infrigement and those that
failed.  In my non-lawyerly opinion it goes to show that perhaps the
most effective fair use defences against a law suit are to get a better
lawyer than your opponent and to shop around for a sympathetic judge.

While the U.S. fair use doctrine as enacted states what must be
considered it does not say that that is all that must be considered.
Apparently the British fair dealing law is not as generous in this

     Rick Parker