Fraction of AGN with [O III] FWHM greater than a given value for FWHM_Avg (left two panels) and FWHM_B (right two panels). Top two panels: full sample of this work, and the bottom two panels show the subset with radio luminosities of log[L_1.4 GHz/W Hz⁻¹] = 23.5−24.5. The cumulative distributions are shown for all the sources in each bin (blue curves) and split by our classifications of compact and extended radio sources (orange and green curves, respectively). Extreme ionised gas velocities are more prevalent when the radio emission is compact; e.g., components with FWHM_B >  1000 km s⁻¹ are four times as likely in compact sources in the log[L_1.4 GHz/W Hz⁻¹] = 23.5−24.5 sample (bottom right panel).