I looked at this a while ago

http://www.noelwatson.com/blog/PermaLink,guid,ee7d3f3a-bef3-4a84-bf29-f0067aa3ad3e.aspx

and wondered whether there were still arbitrage opportunities to be had - I concluded that it was unlikely.

I had a back of 2.96 outstanding on Scotland for the upcoming game against Wales. The bet was taking a while to get matches as it was greater then was being offered by the layers. I checked back and noticed that the lay side was at 100.1% - an arbitrage opportunity. Now obviously, the margins here are tiny, but it surprised me that the book stayed like that for about a minute, until an automated application (I assume) placed three lays. I would've expected the automated apps to either ignore the bet altogether as the margin was so small, or to place bets instantly. I guess it takes a while to iterate through all open books.

Maybe there are still opportunities out there