7) Andre Santos – £6m from Fenerbache – August 2011
Santos was sort of the joke figure at Arsenal when he arrived; a loveably, funny, slightly overweight full back who could just as easily score a goal than cost one.
But his Arsenal career ended the day he was seen on TV swapping shirts with the recently sold and now hated Robin van Persie at half-time when Arsenal played Manchester United at Old Trafford in 2012 and were losing 1-0 thanks to an RVP strike.
He got the shirt but went from cult hero to zero and two months later was shipped back to Brazil to play for Gremio on-loan and eventually sold.