JET Optimised Shear (OS) experiments have produced internal thermal transport barriers (ITB)1 which clearly show up in the plasma density and temperature profiles. This paper studies the influence of an ITB on impurity transport in JET OS plasmas. Two species are studied: intrinsic carbon and injected nickel as a trace impurity. The possible relation of particle transport to pressure gradient , radial electric field, and toroidal and poloidal rotation velocities and is investigated. We take two plasmas as examples which represent two groups of discharges with strong and weak transport barriers. Figure 1 shows the gradients in ion temperature and toroidal rotation profiles in these two OS discharges with different strength of ITB.