Distribution of LoTSS Deep Field sources as a function of redshift, z_Best (Z_BEST in our catalogues), and radio power L_150MHz assuming a constant spectral index of α = −0.7. The colour scale illustrates the combined number of sources across the three deep fields with a logarithmic scale. The 5σ luminosity limit for the wide area LoTSS DR1 (Shimwell et al. 2019) data is plotted in red for comparison.