RAF GR.1As carried a suite of IR recce sensors in the forward fuselage in place of the cannons. These were called TIRRS (Tornado Infra-Red Reconnaissance System) and consisted of two IR cameras facing left and right, looking through rectangular windows in the fuselage sides, and an IR linescan unit in a bulge underneath. The standard radar and the rest of the weapons capability was retained, although they may not have had black boxes for every option. Radically (for the time) there were no visible light spectrum cameras (it was felt that imaging IR could get all the data that was needed) and there was no film either: everything was recorded straight to videotape. This was actually the first all-digital photo-recce system in the world.
TIRRS was very good, but it was a low-level system, so the GR.1As used conventional external pods for medium and high-level work. The GR.4As retain TIRRS, but since all modern ops are medium level, it gets very little usage these days.
