Measurements have been made of the plasma parameters in the boundary layer over a wide range of operating conditions in JET. The plasma currents have been varied from 1MA to 5MA and the average density in the range from 1 to 5¥1019 m­3. It has been observed that the edge density increases with line average density and the edge temperature decreases. Emphasis has been placed on testing data under steady state conditions of plasma current and density. The temperature and density at the last closed flux surface (LCFS)has been modelled using global particle and energy balance. It is shown that good quantitative agreement is obtained with experimental data for the density and the total particle and flux. In a second stage using the global energy balance a crude attempt is made to estimate the impurity influx and hence the radiation from the plasma. Results give the right order of magnitude and the correct trends for the variation of the edge temperature with density and input power.