On his way to Australia in October 1973, Lamb stopped off in South Africa and Rhodesia (today Zimbabwe), where he cut his travels short to enlist in the Rhodesian Army. According to Barker, Lamb travelled to Africa with this intention all along. Rhodesia's unrecognised and predominantly white government was at that time fighting a war against communist-backed black nationalist guerrillas who were attempting to forcibly introduce majority rule. Like most of the foreign volunteers in the Rhodesian forces, Lamb mustered into the Rhodesian Light Infantry (RLI), an all-white heliborne commando battalion engaged largely in counter-insurgency operations. He and the other foreign soldiers received the same pay and conditions of service as the Rhodesians they served alongside. "In many respects the RLI was a mirror of the French Foreign Legion, in that recruiters paid little heed as to a man's past and asked no questions," writes Chris Cocks, a veteran of the unit, "and like the Foreign Legion, once in the ranks, a man's past was irrelevant." So it proved for Lamb; keeping his past a secret, he became a highly regarded and popular member of 3 Commando, RLI, noted for his professionalism and physical fitness. "The Rhodesians thought he was a first-class soldier," Barker later told the "Globe and Mail".