Rest-frame 250 μm LF. The red stars are derived from our de-blended catalogue in COSMOS (filled red stars: our LF above the completeness limit; empty red stars: our LF below the completeness limit). Error bars on the red stars only represent Poisson errors. The black empty squares are taken from Koprowski et al. (2017), based on SCUBA-2 850 μm observations of the COSMOS and UKIDSS-UDS fields as part of the S2CLS. The two faintest points in the Koprowski et al. (2017) measurements in the 1.5 <  z <  2.5 redshift bin (which has the largest dynamic range) were derived using the ALMA 1.3 mm data. The dashed line is the best-fit Schechter function adopted in Koprowski et al. (2017). The faint-end slope of the Schechter function was found to be α = −0.4 in the 1.5 <  z <  2.5 redshift bin in Koprowski et al. (2017) and was kept fixed in the remaining three redshift bins. The vertical dotted line indicates the location of the characteristic luminosity, i.e. L_* in Eq. (1), as derived in Koprowski et al. (2017).