7. Denilson - £21.5m | Sao Paulo to Real Betis in 1998
Denilson made history twice - not only did this transfer break the world-record for a biggest fee paid for any player, but the Brazilian star also won the title of the first £20 million plus player.
Again, the weight of expectation proved too much and Denilson failed to live up to his burgeoning reputation.
Real Betis were relegated in 2000 with Denilson in the side, though to his credit he did help them return to La Liga at the first time of asking.