Improved lighting units are disclosed comprising a casing (14, 114) and a
heat sink (11, 110) mounted to the casing (14, 114), a
light source (6, 106) mounted to a front side of a circuit board (8, 108), the circuit board (8, 108) including control circuitry for the
light source (6, 106), the
heat sink (10, 110) provided in
thermal contact with a rear side of the circuit board (8, 108) and a lens arrangement (12) located at the front side of the circuit board (8, 108), the circuit board (8, 108) and the
light source (6, 106) being located in the casing (14, 114) wherein the circuit board (8, 108) comprises a
ceramic circuit board, the arrangement being such that heat generated in use by the light source (6, 106) and control circuitry is transferred by conduction through the circuit board (8, 108) to the rear side of the circuit board (8, 108) and into the
heat sink (10, 110).