5) Andre Santos (Fenerbahce to Arsenal, 2011)
A real panic buy, Andre Santos initially looked decent enough for Arsenal but went quickly downhill with some sluggish and error-prone displays.
6) Radamel Falcao (AS Monaco to Manchester United, 2014)
Only a loan signing, Radamel Falcao was still a huge waste of money in terms of wages and his £6m loan fee, and was not much better than Welbeck, the player he replaced on deadline day last summer.