In the spring of 1760, the British garrison at Québec, commanded by James Murray, found itself the target of a French army intent upon the recapture of the colonial capital. Led by the exceptionally able François de Levis, the French hoped to surprise Murray’s outnumbered and isolated army, but even as the French embarked at Montreal on 20 May, Murray was writing that he had “received certain intelligence” of French preparations and had taken appropriate precautions. Much of this foreknowledge came from British spies working behind the French lines. Although prior to September 1759 the British had not possessed a single operative in Canada, Québec, now in British hands, became the base for a modest espionage organization which proved capable of scattering informants throughout the towns and countryside of New France and recruiting at least one agent in the confidence of the very highest officials of the colonial administration.
MacLeod, Peter "Treason at Quebec: British Espionage in Canada during the Winter of 1759." Canadian Military History 2, 1 (1993)