Comparison of |L_Z| distributions for samples of prograde (blue) and retrograde (orange) stars with disc-like orbits (as defined in Fig. 2) and low orbital eccentricity (ϵ < 0.5). All stars with [Fe/H] ≤ −1.5 are included in the comparison. The probability that the two samples are drawn from the same parent population in |L_Z| according to a Kolmogorov–Smirnov test is also reported.