This link to a government web site might be useful to some of you out there;

http://www.legislation.gov.uk/uksi/1989/1796/schedule/4/made

Ooops finger trouble should work now......

[Edited on 21/4/11 by snowy2]

Check the link chap, it's not working

is it worth making this link a "sticky" as it seems to be a recurring question.
If you click on the "next schedule" button on the top of the page it takes you through the other related information on the various lighting requirements for cars.