Average stellar mass (taken as the mean in log₁₀ space) of the LoTSS Deep radio population as a function of redshift, z_Best (Z_BEST in our catalogues), and radio power L_150MHz – assuming aconstant spectral index of α = −0.7. The 5σ luminosity limit for the wide area LoTSS DR1 (Shimwell et al. 2019) data is plotted in red for comparison (with the solid line representing the redshift range with high quality photo-z for the comparable galaxy population D19). The typical M^⋆ for the galaxy SMF at these redshifts is marked on the colour scale for reference (white dashed line).