In situvane tests were carried out in a number of different muskeg deposits to examine the mechanism of failure and the effect of variation in vane size and speed of testing. The failure mechanism in peat was found to be similar to that in soft clays. The apparent shear strength varied with vane size but was independent of testing speed. There was an optimum vane size of 10 cm diameter.Block samples were obtained from one site for laboratory vane tests to investigate anisotropy in the strength of the peat.In situtests for anisotropy using vanes of varying shape confirmed the laboratory results, and showed that strengths on the vertical plane could be 100 % higher than those on the horizontal plane.