A short review is given of U.K. research into temporal variations in sea surface topography using data from Seasat and the currently operational US Navy Geosat. Investigations from Seasat have included the North Sea validation experiment, the extraction of regional and global ocean tide signals,and the study of the oceanic mesoscale. Preliminary work in progress on the first year of Geosat data is concentrated on the mesoscale variability of the north-east and south Atlantic Ocean, the latter including a comparison to sea level changes observed at the islands of Tristan da Cunha and St Helena. The future plans of the U.K. altimeter community for using ERS-I and TOPEX/POSEIDON data during the WOCE period are summarized.