Just as a follow up to my previous post....
As far as I can gauge, there are a fair spread of opinions around the bases as to why/how this could have occured.
In my experience MON is an organisation with a weath of expertise, tech know how, and most importantly training ethos.
The lessons taken from this incident will be replayed, analyzed, disected, and poured through by our training departments for the next 10 years, with an emphasis on the error chain and CRM aspects of it.
I would also like to add at this point that MON as a general rule respects the fact that crews are human, and that we make mistakes, the company tends to train rather than apply punitive measures.
Like P Pete's employer, MON have an extensive and IMHO innovative CRM programme (although depending apon who you talk too, the opinions can vary a bit), we operate into and out of some fairly challenging places (GIB, Skiathos, Samos, INN, and a few more besides) with specific and well understood/reviewed procedures.
As I've said before, my personal opinion of the error chain is that this began in the weeks and months previous. I for one can hold my hand up to switching freq's close to the ground.