X-ray morphological disturbance. Left: normalised concentration parameter–centroid shift diagram for all the clusters of the sample with available X-ray observations. The black dashed line is the regression line. The green cross marks the projection on the regression line of the cluster with disturbance = 0. Right: distance of radio halos (black points) and upper limits (red arrows) from the mass–radio power correlation (BCES Y|X method) versus X-ray morphological disturbance.