Abstract: A tube for interconnecting combustors (11, 12) in a gas turbine combustion system for ignition purposes. The tube comprises three elements: two outer tube sections (15, 17) connected to respective combustors (11, 12) and an inner tube section (16) coupling the two outer sections (15, 17). The ends (20) of the inner tube section (16) protrude somewhat into the outer sections so that air inlet through holes (19) in the outer sections in the vicinity of the two couplings produces cooling air flow (14) adjacent the inner surface of the tube in opposite directions. The bi-directional nature of the air flow (14) substantially prevents any mechanism by which hot combustion gases (10) are carried between the two combustors by the cooling air, thus providing effective tube cooling and prolonging the life of the tube.