A few days ago it was my Brothers Birthday so in all nature I got him an Ork big 'ard battleforce as well as the Island Of Blood Set. So after a few hours the
WHFB battle was ready I was playing skaven (despite the fact I play High Elves) and He was feilding the High Elves. Rather foolishly I told about flanking with the faster units

. However I discovered that he couldn't flank me! My skaven were all fine in perfect distance of each other but because of my tight pack formation he failed.
So cut a long story short Tight-Knit against fast/flanking type armies.
Also don't play skaven the fail