As Harry shouted ‘Expelliarmus!’, Voldemort cried, 'Avada Kedava!’
A jet of green light issued from Voldemort’s wand just as a jet of red light blasted from Harry’s.


'Avada Kedavra!’
The bang was like a cannon-blast and the golden flames that erupted between them, at the dead centre of the circle they had been treading, marked the point where the spells collided.