A comprehensive baseline shore survey of macrobenthos within the Folkestone Warren SSSI was carried out, with transects established at Shakespeare Cliff, Abbot's Cliff and Copt Point for future monitoring of the impacts of the Channel Tunnel construction works. The most serious direct impact of the works upon the coastal environment is the proposed use of the foreshore within the SSSI for reclamation of a large construction platform and the disposal of excess spoil from the tunnel works. Transect lines were marked and levelled, shore profiles constructed and the major floral and faunal bands and zones identified and levelled. Full species lists were produced and quantitative or semi-quantitative records made of dominant species. The population structure of some common species was recorded. A further 10 sites between Brighton, Sussex and Birchington, Kent were also surveyed. General shore descriptions are given for each site and details of the flora and fauna present analysed within their major assemblages and zonation patterns. Overall algal species occurrence in the south-east is discussed and an ordination of species from a wide range of British sites carried out. Notable records from the survey area include a number of ephemeral, apparently rare species and many are at their eastern-most limit of distribution in the English Channel, although the restricted period of study resulted in generally low species totals. Twenty-three different assemblages ('communities') are described and related to other phytosociological appraisals in literature. The absence of some of the major assemblages is attributed to the physical characteristics of the chalk shores and the absence of suitable habitats at some sites. Six major faunal zones are described and assemblages of macro-invertebrates from under-boulder and over-hang habitats recognised. Fifty new invertebrate records for kent and Sussex were obtained. The absence of records for other areas of coastal chalk in England is noted. All sites visited are ranked in order of importance for their algal and faunal habitats and diversity and recommendations made for the extention or revision of existing SSSI's to incorporate areas of high marine biololgical interest. The length of coast from Copt Point to Abbot's Cliff, including unusual chalk marl areas in East Wear Bay and near Abbot's Cliff, is thought to be one of the most important marine sites between Yorkshire and the Isle of Wight, with The Pound, Eastbourne identified as the most important site in the south-east after Copt Point. The report concludes that chalk shores are of limited distribution in the British Isles, with major examples in Kent and Sussex. Locations with other rock types are relatively species-rich and assemblages differ from those on chalk. Overall, south-eastern England is species-poor in comparison with western England, with eastern Kent the least species-rich area studied. Further surveys to include the geologically different coastline of the Hastings area and chalk coastal outcroppings elsewhere in England are recommended.