SCUBA deep fields and source confusion

Deep submillimetre(submm)-wave surveys made over the last three years using the SCUBA camera at the 15-m James Clerk Maxwell Telescope (JCMT) have revealed a new population of very luminous high-redshift galaxies. The properties of this population, and their contribution to the intensity of the extragalactic background radiation field are described briefly, especially in the context of the SCUBA lens survey (carried out since 1997 by Ian Smail, Rob Ivison, Jean-Paul Kneib and the author: a full description of the survey and references to supporting work can be found in the recent catalogue paper). The potential problems caused by source confusion in the large 15-arcsec SCUBA observing beam for the identification and follow up of the results are discussed. The effects of confusion are not important for the study of 850-micron SCUBA sources brighter than about 2 mJy.