“…They cover twice-daily observations to 1961 and once-daily observations thereafter. Programmes were written to identify logically inconsistent observations or combinations of observations, the temporal distribution of errors and observer preferences for particulardigits, and a file was created with details of discrepancies -see Joyce (2000) for further work on temperature anomalies. Notes were prepared to guide users on discontinuities, inhomogeneities and changes in format, for example the inclusion of additional measurements during certain periods.…”