We determine colour gradients of -0.15 \pm 0.08 magnitudes per decade in radius in F450W - F606W and -0.07 \pm 0.06 magnitudes per decade in radius in F606W - F814W for a sample of 22 E/S0 galaxies in Abell 2218 .
These gradients are consistent with the existence of a mild ( \sim - 0.3 dex per decade in radius ) gradient in metal abundance , ( cf .
previous work at lower and higher redshift for field and cluster galaxies ) .
The size of the observed gradients is found to be independent of luminosity over a range spanning M ^ { * } -1 to M ^ { * } +1.5 and also to be independent of morphological type .
These results suggest a fundamental similarity in the distributions of stellar populations in ellipticals and the bulges of lenticular galaxies .
These results are not consistent with simple models of either monolithic collapse or hierarchical mergers .