Now I know why it became so difficult to impossible to book BMI direct flights from London to Yerevan.
I've heard it before as a speculation that this flight became unofficially a transit route to connect London with Tehran.
However, I can confirm that there is nothing 'unofficial' there. Indeed, London -Yerevan BMI flight turned into "London -Tehran via Yerevan", as featured at the Heathrow airport, and most passengers were Iranian or heading to Tehran. I am actually amazed with the numbers of Iranian passengers to and from London taking into account the relationships between these two countries.
Anyway, here I am, in Yerevan... via London - Tehran :)