Mexico’s top legislator this week said that nobody should be surprised by the extent to which drugs cartels have managed to permeate the upper echelons of the country’s security forces.

In an interview with the FT, Gustavo Madero, Senate president, said: ”Mexican society has been turning a blind eye [to the drugs gangs] for years … none of this has suddenly come about this year or even last. It has been around for decades.”