Steven Pemberton wrote:
>> It would be quite clear to a human reading that in an article of some 
>> sort that Tony Blair is the Prime Minister without any additional markup.
> 
> How about if it was an article about the Dutch prime minister? Would it 
> be clear to you then who it was?

Let's see:

   "The Prime Minister, Jan Peter Balkenende, will today travel to..."

I think it's quite clear to a human reader that Jan is a Prime Minister. 
  It's not clear from that sentence which country he is from, but that 
wasn't indicated in original example of Tony Blair either.  However, one 
can assume the sentence would be in the context of an article that would 
indicate such information, or the sentence could have been written more 
like either of these:

   "The Prime Minister of the Netherlands, Jan Peter Balkenende, will
    today travel to..."

   "The Dutch Prime Minister, Jan Peter Balkenende, will today travel
    to..."

-- 
Lachlan Hunt
http://lachy.id.au/