£20.50 Space NK
http://www.spacenk.co.uk/product/shop+by+brand/laura+mercier/141410009+smudge+brush.do
Until now I had been using Ruby and Millie's old eyeliner brush but it wasn't easy to control and hard to gain depth with for the smokey eye look (which I wear every day just in different shades; brown, grey, olive, bronze, plum, black, even navy!)
This brush is great! Absolutely ideal for the job for which it was made. Can't say I love the price though, hopefully it will work out a bargain on a cost per use basis.
XO
Update 08/11/2012
I am still using this brush on a daily basis a year on. I can't recommneded it highly enough. It washes up well and does a great job of smudging. So far it has cost me 6p per day...