Horrific moment four people - including the son of a Greek millionaire and a mother and child - are killed in a giant fireball when his Porsche ploughs into their parked car

WARNING GRAPHIC CONTENT: Footage shows a Porsche smashing into a parked vehicle next to a motorway between Athens and Delphi in Greece and exploding into a giant fireball. Driver Iorgos Vakakis and his passenger were killed instantly as were a 33-year-old mother and her child who were in the parked Honda Civic. Vakakis was the son of millionaire Apostolos Vakakis, the owner of the Jumbo supermarket chain. Horrific CCTV shows Mr Vakakis' Porsche careering off the motorway at high speed a before crashing into the Honda Civic sideways so hard that both vehicles shoot into a building and explode.