A Conference for Assassins — John Creasey

Four heads of state are to meet in London. The usual suspects will be out on the streets attempting to con, or rob, spectators. But this is not the major problem faced by Scotland Yard's finest, Commander George Gideon. It is known that assassins are planning the murder of at least some of the visiting notables, plus anyone else who gets in the way. Gideon's mission is to do just that!