\label{fig:veronica} Sensitivity of the W mass measurement to the mass $m_{\tilde t_1}$ of the lighter supersymmetric partner of the top quark (horizontal axis) as a function of the difference $\delta m$ between the masses of the two stop squarks (vertical axis), from the analysis of Ref.~\cite{1207.7355}. The colours indicate that measurements of the W mass with a precision smaller than 5~MeV (blue), 1~MeV (red) and 500~keV (green) would be sensitive to a stop mass of 850~GeV, 1.9~TeV and 2.6~TeV, respectively, independently of the stop decay modes.