The existing method of producing radio maps from interferometric data set is based on the assumption that there is a two dimensional fourier transform relationship between the sky brightness and the measured visibility. In mapping of a very wide field, this basic assumption breaks down due to various practical problems, e.g. bandwidth smearing. We present a wide-field mapping technique which is aimed at resolving some of these problems. This technique has been successfully applied to our MERLIN observations of the 5C12 region covering an area of 1800”×l800”.