Infrared luminosity (L_IR) against photometric redshift for the NEP-Deep field (black and red dots) and the Wide field (blue dots), with the selection method detailed in the legend. The red dashed line shows the limit for ULIRGs L_IR >  10¹² L_⊙: above which the sources are either ULIRGs (50%) or hyperluminous infrared galaxies (HLIRGs; L_IR >  10¹³ L_⊙) (36%). The remaining sources below the line (14%) are classified as luminous infrared galaxies (LIRGs, 10¹¹ L_⊙ <  L_IR <  10¹² L_⊙) The galaxies selected with the SCUBA-2 method have the same number of photometric bands as the sources selected with SPIRE in the NEP-Deep field, however, the SPIRE colour criteria select, on average, more luminous sources (15 % more) than galaxies selected with SCUBA-2.