Thick film heating element

A thick film heating element 1 comprises a substrate 2, an insulating layer 3 formed on the substrate, one or more heater tracks 5 formed on the insulating layer and one or more connection pads 4 connected to the one or more heater tracks, wherein at least one of the insulating layer, heater track, and connection pads include glass or ceramic fibres, for example as a composite material in a matrix of glass or ceramic material, such as a ceramic matrix composite (CMC) material. The heating element may further include a cover layer or a temperature sensor track including glass or ceramic fibres. Ceramics such as boron nitride or alumina may be used as fibres to add strength to the layers. The thermal conductivity of the layers may be increased by adding fibres of a ceramic with high thermal conductivity such as silicon carbide or silicon nitride. The fibres may be introduced into an enamel which is then sprayed or screen printed onto the substrate to form the insulating layer, or the enamel and fibres may be sprayed separately onto the substrate.