An electrical temperature sensor 10 comprises a liquid crystalline material 12. First and second electrically conductive contacts 14, 16, having a spaced relationship therebetween, contact the liquid crystalline material 12. An electric property measuring device is electrically connected to the first and second contacts 14, 16 and is arranged to measure an electric property of the liquid crystalline material 12. The liquid crystalline material 12 has a transition temperature T at which it undergoes a phase change between polar and non-polar phases. The phase change between polar and non-polar phases causes a change in said electric property of the liquid crystalline material 12.