8) Jean-Alain Boumsong (Rangers to Newcastle – £8m – 2005)
The Frenchman looked like a decent performer playing in the Scottish league but the transfer fee was huge, considering that Rangers had signed him for free just six months before he moved to St James’ Park.
Boumsong’s first six months at Newcastle were pretty solid, as he struck up a good partnership with Titus Bramble, but he struggled in his first full season and he was sold for only £3.3m just a year and a half after joining the Magpies.