Abstract: This invention relates to a collapsible packaging sleeve made of a foamed polyolefin material such as polypropylene. The sleeve may be formed from one or more sheets of material joined into a continuous ring, or it may be assembled from separable sleeve parts. The collapsiblity is provided by the removal of material from the sheet(s) to create a recess within the sheet defining a region of reduced thickness. When bent about the region of reduced thickness, the material undergoes the well-known transformation known as “whitening”, enabling it to perform repeated hinging movements.