A rocker housing is configured to enclose a rocker shaft and rocker arms connected to push rods that protrude from a cylinder head of an internal combustion engine. The rocker housing comprises a sidewall configured to enclose the rocker shaft and a top wall extending laterally from an upper portion of the sidewall so as to extend over the rocker arms. The rocker housing further comprises an aperture configured to accommodate a fuel injector or a fuel supply pipe for supplying fuel to a fuel injector of the internal combustion engine. The rocker housing further comprises a fuel return channel extending within at least a part of the sidewall. The fuel return channel comprises an inlet at the interior surface of the sidewall configured to receive excess fuel from the injector; an outlet at an exterior surface of the sidewall configured to output the excess fuel, wherein the outlet is laterally offset from the inlet; and an interior passage extending between the inlet and the outlet. The interior passage is formed integrally in the sidewall of the rocker housing between the interior surface of the sidewall and the exterior surface of the sidewall. The interior passage has a minor component in a direction between the interior surface and the exterior surface of the sidewall and has a major component in a direction of lateral offset between the inlet and the outlet.