Reports wind tunnel tests of wind velocity, RMS velocity fluctuations and energy spectra for the streamwise velocity component in the lee of model fences of permeability 0% 20%, 34% and 50%. Compares results with existing field and wind-tunnel data. Turbulence measurements define the leeward flow regions which are dominated respectively by the bleed flow and by thedisplacement flow. Gives separate empirical relationships between mean velocity and turbulence intensity for these two regions. Finds in these tests the 20% permeable fence gave the best overall reduction in leeward mean velocity. Suggests in practice it may be more cost-effective to build a relatively higher fence of greater permeability.