This paper describes some of the geotechnical issues associated with the foundation engineering for the UK's new Wembley stadium. Predicted and observed vertical pile capacity and load-deformation behaviour of horizontally loaded piles are compared, together with observations and predictions of settlement with depth and time below a deep area of fill. Careful assessment of depth dependant variations of strength, Young's modulus and permeability, and the variation of Young's modulus with mobilised strain are necessary for realistic predictions to be made.