I have included this company in the review section because they offer a good range of tools and hardware including bearings, taps and dies. I ordered a 10-32 UNF* tap on the Tuesday and it was with me on the Friday, despite a 1200 mile journey and the delays of the Christmas post.
They also answer email queries quickly, I received a reply in two hours to an email sent at 7pm.
Web site: http://www.modelfixings.co.uk/index2.htm
*When ARE you guys going to go metric?