Tray attachments for chairs, especially garden and patio chairs, are known. These attachments, however, require the original arm or arms to be modified by the provision of keyhole-type slots (U.S. Pat. No. 5,038,451 to Smith), which is beyond the skill and equipment of an ordinary person and makes the attachment non-retrofittable, or (U.S. Pat. No. 4,798,413 to Capelli) by drilling holes into the armrest or providing a specially modified armrest. U.S. Pat. No. 5,649,737 to Behnke proposes either the use of cloth-peg type fasteners or, again, the provision of holes or keyhole-type slots in the chair arms. U.S. Pat. No. 5,344,115 to Mayne, while not requiring modification of the original armrest, proposes the use of quite intricate, heavy, spring-loaded and thumbscrew-operated clamps that are not only expensive, but also certain to mar the polished surfaces of plastic patio or garden chairs.