Toomre diagram showing space velocities with respect to the Galactic centre. The velocity component V is measured in the direction of the rotation of the Galaxy, U towards the Galactic centre, and W perpendicular to the plane. The position of EC 22536–5304, the Sun, and the local standard of rest (LSR) are marked by the red cross, yellow circled dot, and black plus sign, respectively. The grey, green, and blue dashed lines indicate 2-σ velocity dispersions from Robin et al. (2003) for the halo, thick disc, and old thin disc, respectively. Stars from the sample of intermediate He-sdO/Bs studied by Martin et al. (2017), updated using Gaia EDR3 parallaxes and proper motions are shown in grey. Probable halo stars are labelled.