Haloes of encrusting algae, mostly Hildenbrandia, and cyanobacteria were found on the home scars under the shell of Patella vulgata, beneath the pallial cavity. The presence and area of halo varied between sites. Area generally increased with limpet size and at one site was negatively associated with slope of the shore. It is suggested that the algae provide a resource and may, therefore, play a role in the foraging ecology of the limpet.