To death and taxes as the only certainties in life can, for managers on Planet Football, be added a blunder in the transfer market that comes back to haunt them.

Jose Mourinho can claim enough shrewd business to be in credit: Didier Drogba, Ashley Cole and Diego Costa for Chelsea, Luka Modric and Raphael Varane for Real Madrid look good on his CV.

But the sale of Kevin De Bruyne to VfL Wolfsburg for £18 million in 2014, albeit at a £7 million profit from his arrival at Chelsea from Genk in January 2012, turned out to be a belated blessing for Manchester City. The Belgium international made just three appearances for Chelsea under Mourinho before he decided the player did not meet his requirements and off-loaded him to Werder Bremen on loan.