Red Dean wasn't nuclear tipped and wouldn't have been carried by a Lightning. it was an large Vickers build active radar homing missile for the thin wing 'Supersonic' Javelin. Both the missile and the aircraft were cancelled in 1955/56. The best description of its configuration would be a Red Top on Steroids. The Warhead weight of it was 100 lb HE.The weight of the smallest atomic warheads in development for UK defensive missiles was between 4 and 6 times that.