Since 1975 the SEA-Lanchester energy systems group has been part of the United Kingdom wave energy programme. The SEA-Lanchester Energy Systems Group has developed and tested the design of the SEA-Clam. In an attempt to improve the device energy capture efficiency and the structural strength to weight ratio, the SEA-Lanchester group reconfigured the basic airbag - Wells turbine system from its straight spine form to a circular spaceframe configuration. This development combined with the use of membrane air-bags has achieved remarkable improvements in energy absorption efficiencies, and hence has brought the power costs down into the range of 3. 3 - 5. 6 p/kWh. In the light of this progress, the group is proposing a programme for the detailed design optimisation, construction and performance testing of a 60 m diameter Circular SEA-Clam prototype wave energy device.