Sierra Leone's eleven-year guerrilla war - that left 200,000 people dead - was brief, bloody and mindlessly brutal. It was also the second African war in which mercenaries were hired to counter some of the worst atrocities that Africa had on offer. By the time it ended in 2002, several groups of mercenaries - including an air wing equipped with a pair of ageing Mi-24 helicopter gunships and backed by the British Army and the Royal Navy - played significant...