Nor does he warn us that he has no control over the most powerful government agency in Afghanistan, the dreaded Ministry for the Promotion of Virtue and the Prevention of Vice. The spies of these religious police are everywhere, invisible but always present. So all filming must be done very discreetly.

Now we've been given a permit to film in Afghanistan, first film crew to be allowed to do so by the Taliban government. The problem is you're not allowed to film anybody, you can only film the country and buildings. So doing this walking openly in the street and filming is very much against the law. I could be arrested and our cameras could be taken away and smashed. So as you can appreciate this is not gonna be an easy film to make.

So unsure of exactly what lies in store, we fire up our jeep and head for the airport. Our destination, Herat, once one of the greatest centers of learning in Asia, it was also where one of the greatest spy games was played out.

The Afghan city of Herat is 400 miles west of Kabul as the crow flies and it's been a battleground for thousands of years. In its day, it was one of the greatest centers of culture and learning in medieval Asia. The city is on Afghanistan's western border with Iran. From here I'll head northeast towards Mazar-e Sharif before I go to Bamiyan. And once more I'm faced with delays.

discreetly: carefully and prudently, especially so as to avoid giving offence or attracting attention

as the crow flies: in a straight line across country