Tim Hall 
Earth Swarm [EPUB ebook] 

KILLER DRONES ATTACK!Terrifying drones controlled by artificial intelligence are destroying London . . .Genius scientist John Strider helped create the machines – and he’s disappeared. Only one person has a chance to stop them – his teenage son, hotshot pilot Hal Strider. Hal and his sister Jess are determined to prove their father’s innocence, and to find a way to save the city. But in order to survive, they are going to have to take on a terrible and remorseless foe.THE MACHINES ARE COMING . . .