A confinement structure comprises one or more open cells (70) for confinement, in use, of particulate fill materials such as soil, sand or aggregate. The cells (70) comprise walls (72) formed of a composite material comprising a polymeric grid layer laminated to a fabric layer. The walls (72) may be formed from a strip of the composite material comprising one or more living hinges. The cells (70) may be provided with skirt portions (74) that extend from at least some of the walls (72).