CONTROLLER AND METHOD

A controller (700) for a gas turbine (100) is described. The gas turbine (100) comprises the compressor (101) arranged to operate at a rotational speed n, the combustor (102) and the fuel supply means (127) comprising the first fuel supply means and the second fuel supply means, wherein the compressor (101) is arranged to provide air to the combustor (102) at a steady state air mass flow rate mss and wherein the fuel supply means (127) is arranged to supply fuel at a fuel mass flow rate m total to the combustor (102). The controller (700) is arranged to, responsive to the load change ?L to the load L, control the fuel supply means to supply a proportion Z of the fuel mass flow rate m total as a fuel mass flow rate m fuel pilot via the first fuel supply means based, at least in part, on a combustor mass flow rate m t.