A burner tube (1) for use in an oven such as a tunnel oven. The burner tube includes a tubular body (2) having an axially extending slot (3) therein and an inlet (6) for combustible gas, the burner tube further including a metal mesh (4) which covers the slot. In use, the burner tube defines a flow path for combustible gas so that combustible gas entering the burner tube at the inlet passes through the slot and exits the burner tube through a flow area of the metal mesh. The flow area of the metal mesh is greater than the area of the slot at the outer surface of the tubular body. In use, a visible flame is anchored to the flow area of the metal mesh and the metal mesh incandesces to produce radiant heat.