Illustrates some of the results of recent dendroclimatic reconstruction work at the Climatic Research Unit. The work described is restricted to the use of oak ring width chronologies of <i>Quercus petraea (Mattuschka) Liebl. Q. robur L.</i> and their hybrids. Examples are given of simple and multiple regressions on climate variables representative of small and larger regional scale averaging. Preliminary results are also shown of direct spatial reconstruction of patterns of summer mean sea-level pressure over Great Britain. Emphasis is placed on the need to assess the quality of empirically based reconstructions by reference to actual climate data for a period independent of that used for calibrating regression models.