Left: the 870 μm cumulative number counts of ALMA-identified SMGs from the AS2UDS survey. For comparison, we also show the original (deboosted) published S2CLS single-dish counts for this field (Geach et al. 2017), the earlier interferometric SMG counts from ALESS survey (Karim et al. 2013), as well as those derived from SMA follow-up counts of the brightest S2CLS sources from (Hill et al. 2018). The AS2UDS counts roughly follow the same shape as the parent single-dish counts from S2CLS, but there is a systematic reduction in the surface density of SMGs of the order 37% ± 3% (see Section 3.1). The dashed line is the integral of the double power-law fit to the differential number counts. Right: the 870 μm differential number counts for AS2UDS compared to the parent S2CLS UDS. A double power-law functional fit is overlaid as a dashed line, and the fitting parameters are given in Section 3.2.