Advanced tokamak regimes are associated with the increased normalised beta, bN = bt Bta/Ip (bt = 2m0<p>/Bt2) and are often limited by MHD instabilities. Although the presence of an ideal conducting wall increases this beta limit, it is important to know the no-wall ideal b-limit as resistive wall modes can occur above this limit, which strongly depend on plasma rotation, current density profile, distance from the wall etc. It has been found that the Resonant Field Amplification (RFA) of an externally applied helical magnetic field is strongly enhanced when a plasma exceeds the ideal no-wall stability limit, so it can be used as an indication of a no-wall limit. This method of the no-wall limit identification has recently been routinely used in scenario development of high-beta discharges on JET.