A testable prediction of the no-signalling condition using a variant of the EPR-Bohm example

► We propose an example to test the predictive power of the no-signalling condition in quantum mechanics. ► Our formulation relies on the use of EPR-Bohm entangled pairs of particles with Stern-Gerlach apparatus in one of the wings. ► Non-idealness in the Stern-Gerlach set-up may be applied to introduce a relative phase between superposing spin-components, which is precisely constrained by the no-signalling condition.