were shifted by 0.2 degrees in declination to produce a simulated sample of randomly positioned sources. Both this simulated sample and the real sample were matched to the Data Fusion catalogue, and all Data Fusion objects within 30 arcsec of each source were noted. The separation between the matches is shown in Fig. \[fig:matches\]; it is clear that beyond 2 arcsec the number of real and random matches becomes comparable. (Note that the full 10C sample is used in this plot to provide better statistics.)

For those sources classified as compact, the nearest match within 2 arcsec was accepted. If there was no match within 2 arcsec then the source in question was considered to have no optical counterpart. In total, 36 of the compact sources have a match within 2 arcsec and two do not.

For sources classified as extended the positions of all the optical sources were plotted on top of the radio contours (GMRT maps were used for those sources with a GMRT match, WSRT maps were used for the remaining sources). These images were then examined and the sources were also assigned one of the following flags:

1.  probable match – only source within the $3 