  The anomalous behaviour of the charge radii of the isotopic chain of Pb
nuclei has been studied in the relativistic mean field theory. It has been
shown that the relativistic mean field provides an excellent description of the
anomalous kink in the isotopic shifts about $^{208}$Pb. This contrasts strongly
from the Skyrme mean field, where almost all the known and realistic forces
fail to reproduce the observed trend in the empirical data on the charge radii.
The results have been discussed in the perspective of differences in the
ans\"atze of the relativistic and the Skyrme mean-field theories.
