Comparison of the integrated Compton-Y parameters obtained from the Planck and AMI fits, when the cluster size is fixed to that determined from X-ray observations. The one-to-one relation is denoted with the dashed line. The best-fitting linear relation is plotted as the unbroken line. The slope of this latter relation is 1.05 ± 0.05 and the correlation coefficient is 0.80. Note that the same general behaviour (slope >1) is also observed when we fix the cluster size to be that determined from either the Planck or the AMI SZ observations.