The report describes a full-scale trenching trial in which a 5.4 m deep by 20m long by 1.1m wide trench was constructed in soft alluvial soil. Information is provided on the effect of the component activities of the trenching operations on the ground movements which develop both at and below the ground surface in the short and long term and also on the magnitute of the strut loads and the porewater pressure changes caused by the construction