An agricultural implement for mounting on a U-shaped foundation frame supported on wheels for travel over a ground surface where the foundation frame includes first and second laterally spaced mounting beams fixed to and extending from a base. The implement is configured to perform an agricultural operation, to rest on the ground surface when in an idle position, and to attach to the foundation frame when in an operating position. The implement comprises a rigid implement portion configured to be attached to the first and second mounting beams at first and second beam locations remote from the base such that the first and second mounting beams are prevented from moving laterally with respect to each other.