It is twilight in Sardinia. The sun has vanished behind the beetling crags. The crickets have momentarily stopped. The machine-gun-toting guards face out into the maquis of myrtle and olive, and the richest man in Europe is gripping me by the upper arm. His voice is excited. 'Look' he says, pointing his flashlight. 'Look at the strength of that tree.' It is indeed a suggestive sight.An olive of seemingly Jurassic antiquity has grown from a crack in the rock, and like some patient wooden python it has split the huge grey boulder in two. 'Extraordinary,' I murmur. My host and I stand lost in awe at olive power. If Silvio Berlusconi, 67, Italian Prime Minister, is secretly hoping that a metaphor will form in my head, he is not disappointed.