Maybe Balz saw the mission for the trap it was (being a man of superior cunning) and sent his look-a-like on the mission. Obviously, if the REAL Balz HAD captained the boat in question in Portsmouth harbour, he would not have made such a schoolboy error in his interpretation of orders, nor resisted the temptation to destroy all the ships present.
My thinking is that, if Saddam Hussain was clever enough to hire a look-a-like, as was Fidel Castro (neither of which could hope to live up to Balz's intellect and cunning) surely Balz would have a couple of stand-bys ready to go and would have seen this whole Portsmouth escapade for what it was long ago.:hmm:
Balz is probably sitting on a beach somewhere right now in the best James Bond tradition, smirking at our confusion...
