The neutron spectrometry system described in this report is in routine use at the Joint European Torus (JET). Designed for the D-D phase of operations, it consists of a complementary set of compact neutron spectrometers housed in a shielding block in the Torus Hall. The block is raised by a tower to the level of the mid plane of the torus. The collimation system, which has an adjustable aperture, defines a horizontal line of sight with a significant directional component tangential to the plasma axis. The shielding, the spectrometers, and the auxiliary sensors and systems are described. The operating limits of the spectrometers, and the methods of data analysis, are discussed. Examples of analysed data are given.