The market in antiquities

I have been sent a series of questions to consider prior to a workshop this coming week. Among them was this: Which agencies are best placed to interdict trafficking?

I would only like to comment on classical material. But it seems to me that there is a huge difference between being 'best placed' and actually taking action. The hundreds of objects that have been returned from North American public and private collections are a reminder that these examples of archaeological material have crossed several international frontiers: say, from Italy to Geneva; from Geneva to London; from London to New York. Yet there has been free movement through customs and other checks.

The high profile 'seizures' have been the initiative of the Italian authorities. Should it be up to 'source' countries alone?

So how do we answer the question?