Fuel system

A fuel system comprises a supply unit (10) operable to deliver a metered supply of fuel to a supply manifold (14), a staging valve (16) operable to control the supply of fuel from the supply manifold (14) to a pilot outlet (60a, 60b) and a main outlet (54), and control means (24, 42, 70) operable to control the operation of the staging valve (16) to control whether fuel is delivered through the pilot and/or main outlets (60a, 60b, 54) thereof.