1 INTRODUCTION  
2 SAMPLE SELECTION  
2.1 Initial radio source sample  
2.2 Removing infrared counterparts  
2.3 Comparison with previous samples  
3 INFRARED-FAINT RADIO SOURCE PROPERTIES  
3.1 Source stacking  
3.2 Source counterparts at other wavelengths  
3.3 Radio spectral index  
4 MODELLING THE IFRS POPULATION  
4.1 Linear size constraints  
4.2 Modelling the flat-spectrum sources  
4.3 Modelling the steep-spectrum sources  
4.4 Modelling the ultra-steep spectrum sources  
4.5 Comparison with the ‘Optically Invisible’ radio sources of Higdon et al. (2005)  
5 CONCLUSIONS