John Graham-Cumming notes that CRU and the Met Office have come over all open, as these excerpts from the CRUTEM4 paper make clear.
we are able to make the station data for all the series in the CRUTEM4 network freely available, together with software to produce the gridded data (http://www.cru.uea.ac.uk/cru/data/temperature/ and http://www.metoffice.gov.uk/hadobs/).
..and...
The code required to produce the CRUTEM4 fields and timeseries will soon be made available. Note that code previously released for CRUTEM3 cannot be used to exactly reproduce CRUTEM4 temperature series due to changes in processing methodology.